Proceedings of the 2nd International Conference on Innovative Solutions in Hydropower Engineering and Civil Engineering

The paper investigates the influence of variation of web stiffener locations on the sectional capacities of SupaCee sections under bending about the weak axis. The SupaCee is the new section made on the basis of the traditional channel section by adding several stiffeners in the web of the channel section to increase stability. The variation of stiffener locations has specific impacts on the flexural capacities of SupaCee sections about the weak axis. With the asymmetrical character of the SupaCee section about the weak axis, the behaviour of this section is analysed when the moment direction is changed. The flexural capacities of cold-formed steel SupaCee sections are determined according to the Australian/New Zealand Standard AS/NZS 4600:2018. Based on the investigated results, it is found that the behaviour of SupaCee sections depends on the moment directions. Also, the web stiffeners should be kept far from the flanges which will be more beneficial for the flexural capacities of SupaCee sections about the weak-axis.

Maximum displacement and the maximum interstorey drift ratio are the important factors for the measurement of the vulnerability of multistorey buildings. For this reason, in this paper a method was proposed to calculate the maximum displacement and maximum interstorey drift ratio (IDR) values. In this model, reinforced concrete multistorey structure was modeled as an equivalent flexural-shear frame. Maximum displacement and the maximum IDR were calculated according to the Equivalent Static Loads Method and The Response Spectrum Method using the continuum model and the results were tabulated. With the help of the obtained tables by this study, the maximum displacement and the maximum IDR of the regular multistorey structures can be calculated quickly and practically. The axial deformation of the vertical elements (columns and shear walls) were approximately considered in the study. The convergence of the presented method to the Finite Elements Method was investigated by two examples in the last part of the study.

As one of the important methods to survey the foundation pile integrity in most engineering industries in China, ultrasonic testing (UT) has such advantages as determining the position and scope of defects accurately and good operability. In this paper, on the basis of the in-depth study of China’s industrial standards, main parameters for evaluating pile integrity in each standard were extracted, features and deficiencies of each parameter were analyzed in detail, and a multiparameter identification method of ultrasonically testing foundation pile integrity, which takes wave velocity, amplitude and basic frequency as the analytical parameters and outputs quantitative results, was proposed as an effective supplement to the ultrasonic testing of foundation pile integrity. This method has been applied to the result analysis of more than 800 engineering piles, and has obtained high consistency by comparing those results with core drilling results. Among them, $$K_{(i)}$$ , the evaluation index of pile integrity with the pile complete and the buried acoustic pipe flat, is basically closed to the range $$1 \le K_{(i)} \le 1.35$$ ; when $$K_{(i)} > 1.35$$ , all others, except for several points, are $$K_{(i)}$$ dispersion caused by head wave interpretation errors; when $$0.85 \le K_{(i)} < 1$$ , all acoustic lines within this range reflect slight or obvious abnormalities of sound velocity and amplitude and obvious distortion of waveforms, that is, this acoustic line has slight or obvious defects; when $$K_{(i)} < 0.85$$ , all acoustic lines within this range reflect serious abnormalities of sound velocity and amplitude and obvious distortion of waveforms, that is, this acoustic line has serious defects. Conclusion: This method can effectively reduce the impact of changes in critical values of wave velocity and amplitude caused by the misinterpretation of the head wave position, thus providing a rapid and accurate evaluation for the ultrasonic testing of foundation pile integrity for later engineering practice reference.

In order to realize the resource utilization of solid waste, the principle of alkali excitation is used to prepare geopolymers with fly ash, mineral powder and wet carbide slag as the main materials to replace part of the cement as the cementing material for the pavement base. Geopolymer-stabilized crushed stone was prepared by compounding cement and aggregate with geopolymer, and the unconfined compression strength, indirect tensile strength, compression rebound modulus, scour resistance and microscopic X-ray diffraction (XRD) and scanning electron microscopy (SEM) tests were carried out to study the effect of the change of geopolymer content on the mechanical properties of geopolymer-stabilized crushed stone and its mechanism. The test results show that when adding 30% geopolymer, the mechanical properties similar to those of cement can be obtained to a certain extent. XRD and SEM analysis showed that the geopolymer provided appropriate amount of silico-alumina and calcareous components to form calcium silicate hydrate (C–S–H) and calcium silicate (aluminum) hydrate (C–(A) –S–H) condensation. The glue can form a dense structure and increase the strength of the mixture.

In order to solve the problem of high-value utilization of coal-to-oil residual direct coal liquefaction residual asphalt, it is compounded with SBS and aromatic oil to modify the matrix asphalt, and 9 compounding schemes are designed using orthogonal experimental methods. Dynamic frequency sweep tests using DSR and a simplified Carreau equation model fitted to the complex viscosity to obtain its zero shear viscosity; the creep recovery rate, irrecoverable creep flexibility and irrecoverable creep flexibility difference of each modified asphalt were determined by MSCR at different temperatures and stress levels, and the high temperature rheological properties of 9 composite modified asphalts were evaluated by grey correlation analysis of zero shear viscosity and high temperature rheological parameters. Bending beam rheological experiments were carried out on the aged composite modified asphalt to analyse its low temperature rheological properties based on the viscoelastic parameters and linear fitting of the Burgers model. The results show that: The high temperature deformation resistance of DCLR composite modified asphalt are better than the matrix asphalt, the most influential modifier is SBS, and the higher the dose, the stronger the high temperature deformation resistance. The unrecoverable creep flexibility Jnr3.2 at 70 °C can better respond to the high temperature performance of asphalt, the ratio of 9% DCLR + 4% SBS + 2% aromatic oil DCLR composite modified asphalt with the best high temperature performance. Burgers model can better reflect the creep process of asphalt, DCLR composite modified asphalt has some defects in low temperature performance, the higher the dose of DCLR, the poorer the low temperature performance of the composite modified asphalt. The low temperature sensitivity of DCLR composite modified asphalt has been reduced, low temperature crack resistance has been slightly enhanced.

In order to investigate the anti-corrosion effect of coated steel of steel bridge, Q345 steel plate specimens with three types of coatings, including zinc coating, aluminum coating and zinc-aluminum coating, are produced by the arc spraying technology. In the present study, chlorine corrosion tests are performed to investigate the influence law of different coating material and its thickness on the corrosion degree. Then the calculation results of two corrosion indicators are compared and analyzed. It is shown that the two corrosion indicators reflect the same corrosion law of three kinds of coating steel. The corrosion of all coated specimens is obviously severe in the early stage and gradually gentle in the later stage. It is also found that during the whole corrosion cycle, the corrosion rate of aluminum coating is smaller and change slower than the other two kinds of coatings, whereas the coating thickness of 200 μm of aluminum coating changes significantly. Therefore, aluminum coating is recommended as a priority, and the recommended coating thickness range of which is 100–150 μm.

In this paper, the construction process of the diversion tunnel of Er-Jia-Gou Reservoir in Harbin is numerically simulated. Based on Biot consolidation theory and porous elastic medium theory, considering the influence of groundwater seepage during the construction process, a three-dimensional fluid solid coupling model of the tunnel is established to simulate the seepage field, stress field and displacement field changes during the construction process. According to the calculation results, the distribution of pore water pressure and stress around the tunnel during the construction process is analyzed, and the variation rules of pore water pressure, stress and the displacement of the vault and arch bottom of the tunnel are obtained when the shallow tunnel construction passes through the sudden change area of rock mass. Finally, the influence range of the sudden change area of rock mass grade in the tunnel construction process is determined: pore water pressure, stress and vertical displacement will be affected at 20 m from the sudden change area. The results of the paper can provide reference for the safe construction of shallow tunnels.

The shield construction is a mature tunnel construction technology. Grouting behind segment wall synchronously during shield construction is an important measure to control stratum deformation, reduce ground settlement and prevent tunnel water seepage. The quality of grouting can significantly affect the quality of tunnel construction. The method of grouting quality judgment in early tunnel construction is inefficient and uncertain. To ensure the safety of tunnel structure, it is an urgent technical innovation to study the non-destructive testing technology for grouting effect of shield segment wall. Nowadays, the general Non-destructive testing methods include ground penetrating radar detection and seismic wave detection. These two methods can meet most of the needs of grouting defect detection behind the wall, but also have their own advantages and disadvantages. Therefore, this study proposes the combination of ground penetrating radar and seismic wave method of shield tunnel wall after grouting defects Non-destructive detection method, first, ground penetrating radar is used for scanning probe shield wall after grouting, and then according to the seismic wave method is used to further verify the results for some suspected injury, while ensure the detection efficiency to improve recognition accuracy. Finally, the defect detection and verification of the proposed method was carried out based on the shield segment model test platform, and this proposed method was successfully applied to the actual project of a metro line in Foshan.

Guangzhou metro line 1 is one of the first to adopt floating slab track in the Chinese mainland, it has been in operation for more than 20 years up to now. In order to obtain the vibration reduction performance of the floating slab track after long service, systematic field test and laboratory test are carried out. The results show that: (1) The rubber bearing of floating slab track keeps good appearance. (2) The measurement results of shore hardness and elongation at break show that, the rubber bearing has a certain degree of hardening after long service. Other mechanical properties of the rubber bearing still meet the design requirements. (3) The first natural frequency of the floating slab track is 33.9 Hz, its vibration reduction effect keeps good, the test result is 12.9 dB. The effective damping frequency band of the floating slab track is above 35 Hz. (4) The vertical dynamic displacement amplitude of rail and track bed is lower than the limit value given in relevant specifications. (5) The test results show that after 20 years of service, the floating slab track is in good condition, it’s still qualified to maintain normal service.

In order to study the influence of the arrangement of thermal insulation floor on the thermal insulation and mechanical properties of hollow slab, ABAQUS is used to establish the model of thermal analysis and mechanical behavior of hollow slab. By investigating distribution of temperature, distribution of heat flux, damage and deformation of floor, deformation of mid-span deflection and other characteristics of the floor section, it is concluded that although the transmission of heat can be effectively obstructed by the thermal insulation slab, the heat will be transferred to the interior of the floor through the gap between the thermal insulation slabs. The arrangement of thermal insulation slab is not the main factor which affect the thermal insulation properties of the floor with the same coverage area. Different arrangement of the thermal insulation slab has a certain impact on the mechanical performance of floor. It is recommended to arrange the thermal insulation slab in equal sections to fully improve the contact area between steel bar and concrete, which can effectively provide the bearing capacity of the floor.

Slurry ratio is a crucial link in the construction of bored pile, which directly determines the quality of bored pile. In order to determine the key performance parameters of the slurry required to form piles in the deep sand layer, relying on Huizhou north station engineering, an orthogonal test of slurry proportioning was designed and carried out, and SPSS statistical analysis software was used to carry out bivariate correlation analysis and multivariate stepwise analysis of the test results, combined with the slurry performance index test regression equation and using MATLAB software optimization processing, slurry optimal mix ratio and verify, the research results show that: orthogonal test screening value, software calculation value, test value is not different. Conclusion: The results show that bentonite and CMC have significant influence on slurry indexes, while Na2CO3 and PHP can adjust slurry performance to meet the slurry use standard; the optimal mix ratio is 148 g bentonite, Na2CO3 5.2 g, CMC 3.5 g, PHP 0.05 g; the slurry ratio test analysis and treatment, and the optimization mix ratio is feasible and reasonable, class I pile proportion more than 98% to meet the actual engineering requirements.

Socket-and-socket wheel-buckle steel pipe formwork support frame is a new formwork support system, with fixed component specifications and fast erection speed, which can significantly improve the construction efficiency. Its application performance is different from that of fastener-type, bowl-buckle-type and plate-buckle-type, and there are not enough experimental and numerical analysis results to consult. Therefore, based on the bearing capacity test of the basic bearing units of socket-type wheel-buckle steel pipe formwork support, the finite element software ANSYS is used to conduct numerical analysis of 12 groups of basic bearing units, and the influence degree of vertical bearing capacity of different specifications of unit supports is studied by stud spacing and wedge tightness of cross bar plug. It is pointed out that the stiffness of formwork support in the vertical and horizontal directions should not be too different in the construction process.

Cold-formed steel structures have been widely applied in structural buildings with advantages in manufacturing, transportation and assembly. Holes can be pre-punched in the sectional members to allow technical pipes to go throughout such as electricity, water or ventilation. This affects the capacities of these such members which have been considered in the design standards in America or Australia/New Zealand. The paper, therefore, investigates the effects of web holes on the capacities of cold-formed steel channel members under compression or bending. Their capacities can be determined according to the American Specification AISI S100-16. The investigated results are the base for analysing the effects of web hole dimensions on the behaviors and capacities of cold-formed steel channel members. It was found that the capacity reductions were obtained for compressive members with the increase in hole sizes, but the flexural capacities were noticeable increase with the increase in the hole heights.

Anti-slide pile is one of the supporting structures commonly used in landslide treatment, while the determination of pile location is empirical. A highway landslide in Yunnan Province was selected as a study case, this paper proposes a method to determine the anti-slide pile location based on the point safety factor distribution of sliding surface. The study found that the local sliding surface has a large value of point safety factor in the anti-slide section. With increase of the proportion of the anti-slide section, the anti-sliding ability of the slide surface can be fully utilized, and the reinforcement effect of the anti-slide pile will be great. Using the point safety factor to determine the pile location is a quantitative method, which enriches the design theory of landslide support structure.

In order to improve the comprehensive performance of pervious concrete, nano-silicon and polypropylene fiber were added to pervious concrete to study the change of performance of pervious concrete. Firstly, the effect of single doped nano-silicon on the properties of cement slurry and pervious concrete was studied, and the optimal water-binder ratio and nano-silicon content were determined. Based on this, mixed polypropylene fiber with different proportions of length of 18 mm to determine the reasonable amount of polypropylene fiber. The results showed that the compressive strength of pervious concrete was the highest when the nano-silicon content was 0.5% and the water-binder ratio was 0.32. Based on this ratio, the maximum compressive strength can be obtained by adding 1.0 kg/m3 polypropylene fiber, and the compressive strength of 7d and 28d increased by 29.9% and 42.2%, respectively. Adding 1.5 kg/m3 polypropylene fiber was the most beneficial to improve the freezing resistance of pervious concrete. For example, after 300 freeze–thaw cycles, the compressive strength residual rate was 62%. That's much higher than the 40 percent that was found when nano silicon was mixed alone.

The preparation of seawater sea-sand recycled concrete (SSRAC) by combining seawater, sea-sand and recycled coarse aggregate is of great significance for the utilization of marine resources and environmental protection in China. The sulfate corrosion test in this paper uses dry wet cycle to simulate the alternating dry wet environment, and compares the ordinary concrete (OC) and freshwater river sand recycled concrete (RAC) to study the mechanical property deterioration characteristics of SSRAC in dry–wet cycle (30d, 60d, 90d, 120d). The results show that with the increase of the dry–wet cycle, the apparent damage of SSRAC gradually extends from the diagonal to the periphery, and finally the cracks spread all over the whole. The mass, strength and strength corrosion resistance coefficient of SSRAC show the same law as OC and RAC, which increase first and then decrease. The resistance of SSRAC to sulfate attack is lower than OC and slightly higher than RAC, and the strength corrosion resistance coefficient is lower than 75% at 120 times of dry–wet cycle.

The application of FRP composite is quite well demonstrated in strengthening on RC structures but on strengthening of steel structures is still being investigated by many researchers. The aggressive marine environment can cause corrosion to the offshore pipelines which would affect the structural performance such as pitting corrosion which could be considered as the most destructive corrosion was simulated in this research. This study had attempted to carry out experimental investigation of effectiveness of FRP composite repair system on offshore pipelines subjected to pitting corrosion under axial compressive load. 3 groups of specimens have been categorized such as intact, corroded and repaired. Results such as compressive peak load, failure modes and load–displacement behavior were concerned in this study. The pitting corrosion has been investigated and proved that it has significant effect on the ultimate strength of pipelines. Number of CFRP layer such as 3 layers has been investigated which the results showed the FRP composite repair system capable of strengthening of corroded offshore pipelines. However, more detailed studies are required to be conducted in the future such as consideration of internal pressure in order to expand the understanding of this composite repair system.

Judging from the development status of most super-high-rise building industries in China, “outer frame + core tube” is basically adopted. The appearance of this core tube structure design concept puts forward higher requirements for the construction safety of the main structure. Combined with practical engineering projects, we analyze the safety risks and countermeasures of the outer frame column of the super high-rise steel structure, the safety risks and countermeasures of the cantilever steel beam, the safety risks and countermeasures of the waist truss, the safety risks and countermeasures of the waist truss, the safety risks and countermeasures of the outrigger truss, the safety risks and countermeasures of the tower crown structure are discussed one by one. It ensures the organic combination of engineering safety measures and engineering construction technology. The proposed safety measures are highly targeted and feasible, ensuring the safe construction of the project. The comprehensive application of this project confirms the feasibility of relevant countermeasures, so as to provide reference and help for subsequent similar projects.

Using servo steel support system for active control of deformation during foundation fit excavation has high superiority. To investigate the coherence of the servo support axial force, PLAXIS 3D is used to carry out numerical analysis on the coherence of the axial force applied by the construction and compare with the field test results; Field tests were conducted on the diaphragm wall joint deformation during the axial force application based on the principle of the generation of axial force coherence. The results show that the farther away from the active axial force, from which suffered get the smaller influence, and the size of the applied axial force’s effect on the support in other directions in the order of horizontal, vertical, and oblique. Moreover, the higher the application position of the active axial force of the servo support, the greater the lateral axial force loss rate generated by other supports, while the opposite in vertical axial force loss rate is true. The maximum axial force loss rate is 19%. The deformation of the diaphragm wall joint in the servo steel support zone is more significant than that in the pre-stressed steel support zone. The deformation of the joint will, in turn, affect the axial force.

Different indices have various capabilities to evaluate the high-temperature performance of modified asphalt mixtures. This study aims at investigate the discriminability of high-temperature performance indices. The values of five indices were determined from wheel tracking test, Marshall test and uniaxial penetration test, including dynamic stability (DS), comprehensive stability index (CSI), maximum rutting depth (RD), Marshall stability (MS), and uniaxial penetration strength (UPS). The discriminability of five indices was further examined by entropy weight method and CRITIC method, respectively. The results show that DS, MS and UPS are not appropriate to evaluate the high-temperature performance of modified asphalt mixtures, but CSI and RD show preferable distinguishing ability to evaluate the high-temperature performance. As a consequence, RD is recommended to be employed as secondary index to supplement the CSI in wheel tracking test. The findings of this study will contribute to the optimization of evaluation on high-temperature performance of modified asphalt mixtures.

To avoid brittle collapse of reinforced concrete (RC) structures, RC elements such as beams, columns, and shear walls are invited to ensure a minimum level of ductility. In this paper, an analytical method for predicting the curvature ductility factor of confined RC columns is developed. The stress–strain model of confined concrete provided by Eurocode 2 is adopted, and the effective lateral confining pressure is calculated according to the Eurocode 8. The curvature ductility factor is defined by the ratio of ultimate to yield curvature. In this context, a new hypothesis is adopted to calculate the yield curvature while the ultimate curvature is calculated based on axial load and the mechanical ratios of tension, web, and compression reinforcement. The results showed that the developed method has an excellent performance compared to the experimental results collected from previous researches, where the mean value and the standard deviation of the ratios predicted to experimental factors are equal to 1.02 and 0.17, respectively. Moreover, the calculated coefficient of determination is very close to 1.

Structural applications of composite materials are used in various structures of the oil and gas industry, water supply and sewage systems and a wide range of industries, such as marine, aerospace, and military industries. This paper aims to numerically investigate the influence of local dent caused by an indenter on the buckling behaviour of glass fabric-reinforced polymer cylindrical shells when subjected to external pressure. For this purpose, 24 finite element numerical models with five layers and a stacking sequence [30/-30/30/-30/30] were simulated in ABAQUS. The effect of dent depth (2, 4, 6 and 8 mm) and orientation (0 and 90 degrees) that was created at the mid-height, the 1/3rd and the 2/3rd of the shell height on the buckling behaviour of the composite cylindrical shells were evaluated. The results underscored that whilst the location of the local dent and the depth affected the shells’ buckling capacity, the dent's orientation had minimal effect on the buckling capacity of the cylindrical shells.

Japan is located in the international seismic zone, and is also a resource intensive country. It has unique features in the research and application of ultra-high performance concrete materials. The paper analyzes and summarizes the engineering application cases of concrete strength grade above 150 N/mm2, including structural system, mix design, production process, strength grade, etc. Silica fume composite cement, with strict calculation of sand and stone gradation, improves the compactness beyond the conventional concrete; The super high performance water reducing agent can greatly reduce the water cement ratio and improve the working performance, especially the expansion degree; Organic fiber and steel fiber are especially important in fire resistance, explosion resistance and ductility. Ultra-high performance concrete could improve the seismic performance of building structures and the utilization rate of building area, and new materials could provide more choices for design and engineering application.

BIM technology has been widely used in practical engineering construction projects, especially in the application scenario of mechanical and electrical pipeline synthesis. In residential projects, the electromechanical pipeline in the basement part is the most complex and concentrated in the whole project. Therefore, this paper studies and summarizes the comprehensive application of electromechanical pipeline of BIM technology in residential basement project. This paper mainly studies the implementation process of BIM electromechanical pipeline comprehensive application of four actual residential basement construction projects, analyzes the problems found and solved in the comprehensive application of electromechanical pipeline in residential basement based on BIM, and summarizes the key points that the project construction party needs to grasp in order to complete such projects with high efficiency, high quality and high standard. In addition, according to the implementation experience of actual engineering projects, this paper also puts forward some suggestions on the implementation process of BIM-based residential basement electromechanical pipeline comprehensive project.

In order to study the seismic performance of the steel tube bundle composite shear wall with different constructions. Based on the failure tests of three composite shear wall specimens without steel tube bundle end, with studs and stiffener, a feasible numerical model is established by ABAQUS. The hysteresis curve and energy dissipation coefficient, skeleton curve and ductility of the shear wall were further analyses by varying the axial compression ratio and the spacing of the internal diaphragm. The results show that the stud group and the stiffener group can effectively improve the horizontal bearing capacity, energy dissipation capacity, bearing capacity and ductility of the shear wall. Under the condition of low axial compression ratio, the horizontal bearing capacity of the member with stud is increased by 6.3%; Under the condition of high axial compression ratio, the horizontal bearing capacity of members with stiffeners is increased by 4.5%; The change of axial compression ratio and the spacing between inner diaphragms of shear walls with stiffeners has little effect on their energy dissipation capacity and ductility.

When an existing building has excessive settlement and has no convergence tendency due to foundation problems, the composite piled foundation is often used to partially underpin the upper load. However, considering that the compression properties of the foundation soil have changed greatly, the compressibility index provided by the initial survey report is no longer suitable for calculating the settlement of the reinforced foundation. In this paper, a consolidation test is designed to simulate the compression state of the foundation soil in the process of building construction, reinforcement, and settlement stability. The test results show that the recompression modulus Ers of the soil sample is 2.5–3.5 times the compression modulus Es1-2. In the engineering example, the recompression modulus is used to calculate the settlement of the reinforced foundation according to the settlement calculation method of the composite foundation with settlement-reducing piles, and the results are close to the actual settlement. In actual engineering, in the absence of supplementary survey, it is recommended to obtain the recompression modulus Ers through simulated test or use 2.5–3.5 times the compression modulus Es1-2 to calculate the settlement of the reinforced foundation.

Adverse buried bodies near to ground surface would damage the buildings, and the detailed geometric characteristics of adverse buried bodies is essential for reducing damage and potential risk. To achieve this goal, forward simulation on geometric characteristics of three typical culverts in Chongqing were carried out in this paper. The response characteristics of (ground penetrating radar) GPR profiles caused by geometric characteristics and filling materials change were summarized, and the apexes of diffraction hyperbolas and lateral changes in the reflection pattern were used to determine the dimension and boundary of buried bodies. The comparison between GPR profiles interpretation result and the measured data in the field was used to verify the validity.

Bridge Bearings are important devices for transferring loads between the upper and lower structures of bridges. They can ensure the safety of bridges and regulate deformation. They can also prevent bridge displacement caused by temperature changes, seismic forces, and other factors in various structural types. The status of bridge bearings can effectively reflect the healthy status of the bridge. Monitoring of stresses on bridge bearings can be used to evaluate the healthy status of the bridge structure. However, bridge bearings are installed in invisible locations, and traditional manual inspection methods cannot accurately determine their damage and degree of destruction. In this paper, an intelligent bearing pair is designed to resolve this problem. The designed intelligent bearing status assessment system with multi-level threshold values can trigger a warning when the threshold is exceeded. Experiments have been conducted to verify the accuracy of its signal processing.

Cold regions and snowing weather are widely distributed in Global, which caused a series of problems in road safety, such as icy surfaces of roads, frozen-thaw Circle damage, and traffic jams. This research aims to improve the energy-efficient of electric heating snow-melting tubes for solving the icy and snowy pavement of urban roads. Numerical simulation and in-situ testing experiments is used in the research while the temperature field distribution and snow melting performance of the electric heating pipe heating road system are explored. It is found that the increasing of electric heating pipes cause a great impact on the snow melting effects. Moreover, this study lays the theoretical and experimental foundation for practical applications.

In recent years, steel structures have been widely used in buildings because of their advantages in self-weight and seismic performance. However, due to the great influence of temperature on steel structure, once a fire occurs, it may lead to the destruction of steel structure and even the collapse of the building. In this paper, through the assessment of a steel structure factory after fire, the damage degree of the components and structural integrity of the building are determined, which provides a reliable technical support for the subsequent repair and retrofit work. Based on the extent of damage identified, repairs are performed on the affected members. The analysis results of the rehabilitated structure show that this method is safe and effective.

This study investigated the characteristics of dredger fill after preloading at the DaLian. Granulometric composition test and X-ray diffraction were employed to determine the composition of dredger fill. Mercury intrusion porosimetry was combined to determine the related features of the pore. This paper also discussed the changes in porosity, pore diameter distribution, and morphological characteristics of the pore. Preloading influence depth was established based on pore changes. The results show that: the dredger fill contained numerous clay minerals, mainly illite and illite–smectite mixed layer; and the influence depth established based on pore changes of the area was almost 11 m. Within the influence depth, porosity decreased rapidly as the depth increased, and the main scope of pore volume fraction changes from the scope of 0.06–10 μm to the scope of 0.1–1 μm. When depth was greater than the influence depth, porosity slowly changed, pores with diameters greater than 1 μm show an increasing trend. Thus, the soil was compacted.

Aiming at the problem of comprehensive detection technology and treatment measures for tunnels crossing large karst caves, this paper systematically carried out the research on advanced detection of karst geology and treatment measures of karst caves in combination with the Qinlan Tunnel Project of Tianba Expressway in Guangxi. The comprehensive detection method of “karst geological survey + geological radar detection + advanced horizontal drilling + three-dimensional laser scanning + geological sketch” is used for advanced detection. On the basis of ascertaining the spatial location and development scale of karst caves, the scheme of tunnel excavation after advanced reinforcement and support treatment such as advanced small pipe grouting is determined. It has been successfully applied to the construction practice of Qinlan Tunnel crossing ZK89+110 large karst caves, and the treatment measures of “root pile + lining strengthening” are put forward. It effectively avoids the occurrence of disasters caused by karst caves, and has important reference significance for similar projects.

Deep tunnels will face complex mechanical behavior problems of rock mass during construction and operation, among which the rockburst disaster is particularly prominent. Therefore, how to scientifically predict the rockburst activities of deep tunnels has become an urgent problem to be solved. According to the three aspects of energy conditions, lithology conditions and stress intensity that rockburst must meet, the strain energy storage coefficient (Wet), stress concentration factor (SCF) and brittleness index of rock mass (σc/σt) are selected as the discrimination indexes. On this basis, combining with the method of cluster analysis, some abnormal data are removed and a case database is constructed. Aiming at the defects of traditional prediction methods, this paper proposes a support vector machine method to establish the rockburst prediction model. According to the prediction model proposed in this paper to predict the rockburst situation of several deep tunnel engineering in China. The results show that the tunnel rockburst prediction model based on support vector machine is well consistent with the actual situation, indicating that the model has strong feasibility in practical application.

Based on the practice of Changsha Airport Addition and Alteration Project, this paper refines, studies and summarizes the type, integration and interaction of pipeline information in large-scale and complex project sites, According to the whole life cycle of the Project, four types of pipeline information, including self-owned attribute, system attribute, management attribute and additive attribute, are sorted out. In actual engineering projects, there are two modeling ways, Method I: direct BIM design modeling, Method II: transformation and modeling after CAD design. The difference between Method I and Method II mainly sits on the difference in presentation form. One is three-dimensional and the other is two-dimensional. However, the base of both of them representing pipeline information is attributes and data. As long as these attributes and data can be extracted, information integration can be realized and applied to project management in the later stage. Based on the integrated research on the airport pipeline information, a corresponding BIM collaboration and management and control platform has been developed for the Project, and research results have been applied to the actual management of the project pipeline in an exploratory way, so as to achieve the project management requirements of the airport pipeline in terms of design, progress, cost, prefabrication and processing, and prepare for the later digital delivery and intelligent operation and maintenance management.

Seismic interferometry (SI) can be used to reconstruct a pseudo-acquisition from response of a passive source, while the reconstructed data can be used to recover a portion of the model space that is different from that recovered by the inversion of original measurements. The SI by crosscorrelation requiring the seismic wave field to be evenly distributed, which limits the scope of application of this method. SI by multi-dimensional deconvolution (MDD) broken through the limitation that the wave field must be evenly distributed, but there are still some limitations in some special practices. Interferometric point-spread function (PSF), like the correlation function, is a necessary condition of the MDD method, but in some practices it cannot be derived from the field data. A new MDD method is proposed in this paper that free from PSF, and theoretically proved that it is equivalent to usual MDD. We demonstrate the effectiveness of this method with two numerical examples of one-sided illumination, and the source blurring phenomenon in the results of SI by crosscorrelation is effectively eliminated. The first numerical example is far-field one-side illumination, which can also be treated with the usual MDD, and the comparison of the results shows that the two MDD methods are equally effective. The second example is the near-field one-side illumination, and only the MDD method proposed in this paper can be used because the PSF cannot be obtained.

By conducting numerical simulations of Treasure Island site in 1989 Loma Prieta earthquake, the Hilbert-Huang transform was used to study soil liquefaction. The UBC3D-PLM constitutive model was used to simulate the dynamic behavior of sand, the non-liquefied soil was simulated by Hardening Small Strain model, and the seismic information recorded in the PEER database was used for deconvolution analysis by one-dimensional equivalent linear analysis method, and the within motion was applied. Rayleigh damping is used in the numerical simulation process, and the damping ratio is 5%. Based on the Hilbert-Huang transform analysis, it is concluded that the UBC3D-PLM constitutive model can effectively simulate the dynamic behavior of soil. The amplification of the peak acceleration was from the bottom of Sandy fill to the ground surface, and the low-frequency content was shifted due to liquefaction in the process of transmission to the surface, and the high-frequency content was identified at the surface.

Three-dimensional solid modeling of an OBS anti-trawl sinking coupling frame was carried out using the ANSYS, and modal simulation analysis of the overall structure of the anti-trawl sinking coupling frame was made through the ANSYS Workbench. The natural frequencies and mode shape contour diagrams of the first six modes were extracted. The displacement response spectrum was analyzed, and the equivalent stress and directional displacement contour diagrams were obtained. Simulation results show that the natural frequency of the anti-trawl sinking coupling frame evades the working frequency band of the OBS, which verifies the effectiveness of the anti-trawl structure design.

The uncertainty of pile and soil and slope effect are two of the major factors affecting the horizontal bearing capacity of piles of transmission tower in sloping ground. In order to analyze the influence of the two factors on the reliability of pile, this paper proposes a reliability analysis method for horizontal bearing of pile foundation in sloping ground based on proxy model. Firstly, the analytical model of horizontal bearing of the pile foundation in sloping ground was derived, and corresponding performance functions were constructed. Secondly, by combining Kriging model method with the performance functions, the reliability analysis method of pile foundations in sloping ground is established. Finally, taking a typical transmission line project in mountainous area as an example, the horizontal bearing reliability of pile foundation was analyzed. The results show that the proposed analysis method can quickly converge to the horizontal bearing limit state of pile. Slope effect has more significant influence on horizontal deformation than that of material yield. Among the uncertainty parameters, the bearing capacity of pile foundation is sensitive to the dispersion degree of horizontal force, pile diameter and the elastic modulus of foundation pile.

The soil mudstone slope anti-slip piles are used as the object of study to analyse the pile forces under the action of heavy rainfall. Introduction to the project, description of the general topographic elevation of the area; extraction of seepage potential energy from soil mudstone, calculation of rainfall and rainfall infiltration, assumption of vertical wall backs and horizontal fill behind the wall, calculation of lateral pressure on the rock supported by anti-slip piles, analysis of its damage mode according to the morphology of the bedrock surface and the conditions of the rock outwash structural surface, and calculation of slope stability under the action of strong rainfall. Analysis of the results: setting the length of the anti-slip piles at 15.5–17.5 m is most reasonable under the effect of heavy rainfall.

Sanhekou Reservoir is an important water source for the Han Wei River Diversion Project, which plays a very important role in supplying water to Guanzhong area. Taking Sanhekou reservoir basin as the research object, MIKE21 model is used to simulate the water environment of the reservoir basin. MIKE21 hydrodynamic module is used to analyze the flow field characteristics of the reservoir study area in high flow year, normal flow year and low flow year. MIKE21 water quality module is used to simulate the water pollution of the reservoir, and analyze the maximum concentration value of pollutant migration in 6, 12 and 24 h under four working conditions, as well as the pollution peak value of 5 and 20 km sections. The results show that the overall velocity variation range of the study area in the wet, normal and dry years is 0–0.139 m/s, 0–0.102 m/s and 0–0.096 m/s respectively. In the four working conditions, the maximum pollutant concentration of working condition 1 is 4.76 mg/L under 6 h of pollution leakage, and the peak value of pollutants under the four working conditions of 5 km section is larger than that of 20 km section. In view of the ecological environment problems in Sanhekou basin, reasonable ecological restoration suggestions and measures are proposed.

Daily operation of a hydropower station is conducted to meet the energy requirement. The hydraulic parameters of the downstream are significantly affected by the dam operation, which has a negative impact on the aquatic system. When the multi energy complementary method is used, such as hydro-photovoltaic (hydro-PV) combined power generation, the problem will worsen. Hydropower station A (HSA) on River X was selected to investigate the impact of daily operation. HSA is a part of hydro-PV complementary power generation. The spawning and breeding period of typical fish, April to July, was selected as the study period. According to various scheduling, the changes of hydrological regime were analyzed. The results show that the maximum flow variation was 334 m3/s, and the variations in water surface width and velocity during reservoir operation were between natural conditions. The maximum daily water level variations under the two operating scenarios were 1.6 m and 3.5 m respectively. The remarkable change of water level may have a negative impact on aquatic organisms. Considering the daily variation limit of 1.2 m under natural condition, the relationship between the allowable daily variation of reservoir outflow and the reference base flow was proposed. The results in this paper serve as a technical reference for studying changes in the hydrological regime and lessening their impacts on aquatic organisms in hydro-photovoltaic complementary development.

The phyllite-weathered soil is a regional speciality. It is essential to study the changes in shear strength of phyllite-weathered soil under dry-wet cycles to understand the changes in mechanical properties of phyllite-weathered soil in the process of dry-wet climate and to manage the slope of phyllite-weathered soil. This paper simulated 12 dry-wet cycles on the specimens of remodelled phyllite-weathered soil. Direct shear and SEM tests were conducted on the specimens in the 0th, 3rd, 6th, 9th, and 12th drying paths. The effects of moisture content and the number of dry-wet cycles on the shear strength of phyllite-weathered soil were analysed macroscopically and microscopically. The following conclusions were obtained: (1) The cohesion of the weathered soil of phyllite will be reduced by increasing the number of cycles, and the more the number of dry-wet cycles, the more pronounced the reduction; the internal friction angle of the weathered soil of phyllite will be reduced by increasing the number of cycles, but the pattern of the decrease in the internal friction angle is not obvious. (2) The increase in the number of dry-wet cycles will increase the stiffness and brittleness of the phyllite-weathered soil specimen, and it will change from the weak hardening type of plastic damage to the solid softening type of brittle damage after a certain number of cycles. (3) The SEM test found that phyllite-weathered soil particles in Longsheng, Guilin are large, and most of the particles are in face-to-face and angle-to-face contact, which is easy to form a hollow structure, and the dry density value of the soil in the natural state is small. At the same time, the soil is reddish-brown in colour because of the leaching of Fe2 O3. The shear strength index of the cemented phyllite-weathered soil with Fe2 O3 is more significant than that of phyllite-weathered soil in other areas. The soil has a good shear strength index and a small dry density.

In order to quantitatively evaluate the one-dimensional site seismic response analysis methods, this article selected 2418 ground motion records of Japan KiK-net strong-motion seismograph network and 2418 groups of acceleration response spectra calculated by DEEPSOIL, SHAKE2000, SOILQUAKE and SOILRESPONSE, and then` used the dynamic time warping (DTW) algorithm to calculate the DTW distance between the measured acceleration response spectrum and the calculated acceleration response spectrum. The average DTW distance and change trend in different PGA ranges were compared and analyzed. The average DTW distance of the four methods in weak ground motion were similar, and in the strong ground motion, the average DTW distance of SOILRESPONSE was smaller than the other three methods. The DTW distance of the four methods increased with the increase of PGA, the growth rate of SOILRESPONSE was significantly lower than the other three methods. DTW distance can accurately and effectively reflect the difference between response spectrum, which provides a new method for quantitative evaluation of one-dimensional site seismic response analysis method.

The use of biofilm to repair heavy metal pollution in rivers has become a research hotspot in various countries and has attracted more and more attention. The adsorption of heavy metal ions by biofilm depends on many physical and chemical factors. In this paper, the model and its influencing factors of the adsorption of heavy metals by biofilm attached onto the magnetic fillers containing 10% strontium ferrite were studied. The study found that pH is the most important factor that interferes with the adsorption of heavy metal Cu2+ in biofilm. When the pH is 6.2, the adsorption capacity of heavy metal Cu2+ reaches maximum value. In comparison, temperature has no significant effect on the adsorption of Cu2+ by biofilm. When the temperature increases from 5 to 30℃, the adsorption rate of Cu2+ increased by 11.2% accordingly. This study has important theoretical reference value for heavy metal Cu2+ in-situ repairation in rivers or lakes using magnetic filler biofilm method.

Fiber Optic Gyroscope (FOG) is a kind of rotation sensor with high reliability and long lifetime. Accelerated life test is hard to obtain enough failure data for reliability evaluation. By analyzing failure mechanism, the sensitive environment stress and performance degradation parameters of FOG are determined. Then an accelerated degradation test (ADT) is undertaken to obtain reliability information. Wiener process is introduced to describe performance degradation path and the Arrhenius model is selected as accelerated model. Considering epistemic uncertainty in monitoring, an interval linear regression model for ADT is introduced. Then the reliability of FOG at operating environment stress is evaluated. By discussing the reliability assessment results, the methods in this paper are feasible for FOG.