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2021 | Buch

Advances in Innovative Geotechnical Engineering

Proceedings of the 6th GeoChina International Conference on Civil & Transportation Infrastructures: From Engineering to Smart & Green Life Cycle Solutions -- Nanchang, China, 2021

herausgegeben von: Prof. Yong Liu, Ph.D. Sabatino Cuomo, Ph.D. Junsheng Yang

Verlag: Springer International Publishing

Buchreihe : Sustainable Civil Infrastructures

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SUCHEN

Über dieses Buch

With the development of social and science, new requirements are put forward for geotechnical engineering. Advanced geotechnical techniques were proposed to solve the new challenges in geotechnical engineering. The articles presented in this volume aim to the new development of geotechnical engineering such as characterization of geomaterials, slope stability, application of environmental protection materials and some other geotechnical issues that are becoming quite relevant in today's world.

Inhaltsverzeichnis

Frontmatter
Unsupervised Learning of Pavement Distresses from Surface Images
Abstract
The most common asphalt pavement surface distress is cracking, manifested in various forms, such as transverse, longitudinal, and reflective cracks, governed by different initiation and propagation mechanisms. Being able to timely detect and classify different types of cracks provides critical information for properly maintaining and managing our invaluable road assets. In this paper, a series of classic image processing techniques were applied to pavement surface images to delineate crack patterns. The processed images were projected to a low-dimensional feature space through principal component analysis (PCA). A K-means algorithm is then applied to cluster images in the low-dimensional feature space. The results revealed a meaningful correlation between the crack patterns and the clusters derived.
Ahmad Abdelmawla, J. James Yang, S. Sonny Kim
Physical-Mechanical Properties of Sandstones After Exposure to High Temperature
Abstract
Studying the problems of rock engineering under high temperatures has become a new research direction for rock mechanics. The physical-mechanical properties of rocks under high temperatures circumstances have a great interest in many of engineering applications, such as deep geological repositories for heat-generating radioactive wastes, oil/gas recovery enhancement, underground gasification of coals, exploitation of geothermal resources and the protection of buildings against fire or restoration after exposure to fires. In this paper, the physical and mechanical properties of Jiaozuo sandstone after experiencing heat to high temperatures are studied. The temperature varies in a range from 20 °C to 1200 °C. The studied physical properties include the changes of samples' apparent shape, volume, mass, density, and velocity of longitudinal and shear waves through these samples. The studied mechanical properties include peak stress, peak strain, and Young's modulus under uniaxial compression state. The deterioration mechanism of sandstones exposed to high temperatures is briefly discussed by detecting mineral composition. The test results show that high temperature leads to the changes of apparent shape for sandstone, the temperature does not obviously affect the mechanical properties, and heating reinforces some mechanical properties of sandstone in the temperature ranging from room temperature to 400 °C. When the temperature is above 400 °C, the mechanical properties of sandstone present deterioration with the increase of temperature, the peak stress and Young’s modulus of sandstone decrease in different extents. The peak strain of sandstone increases by a big margin before 800 °C. The deformation of sandstone generally increases with the rising of temperature. From 600 °C to 1200 °C, clear brittle-plastic transition appears in sandstone. Sandstone presents plastic failure characteristics after 1200 °C. Thermal stress, changes in mineral formation, and microstructure due to temperature result in changes in mechanical properties and degradation of sandstone.
Gang Wu, Hong Sun, Gusheng Tong, Wang Yu
Liquefaction Properties of Two Types of Sandy Soil Specimens with Different Compaction Thickness
Abstract
It has been pointed out in laboratory element tests that the liquefaction properties of sandy soils are influenced by differences in specimen preparation methods. In practice, the moist-tamping method has been mostly used in laboratory tests because it allows grain size distribution and moisture content to be widely selected. In this study, a series of cyclic undrained triaxial tests was conducted under different conditions of grain size distribution and compaction thickness to reveal the effects of specimen preparation methods on liquefaction properties of two types of sandy soils. The specimens were prepared using the moist-tamping method. The number of compaction layers were either 1, 4, or 10. The results showed that the liquefaction resistance was influenced by compaction thickness, and its tendency changed depending on the grain size distribution and degree of compaction, Dc. In addition, it was found that a difference in the initial moisture content had an influence on deformation properties during cyclic loadings. In particular, the deformation properties of the specimens compacted under lower moisture content was similar to that of loose specimens. Furthermore, in the case of well-graded sand, there was no significant difference in liquefaction resistance between specimens of 10 and 4 layers; however, the liquefaction properties of a 1 layer specimen were significantly different from those of other compaction layers.
Tomoko Sasaki, Shima Kawamura, Junichi Koseki
The Research of Dynamics Property and Long-Term Settlement About Weathered Argillaceous Siltstone Under Base of Subway Tunnel
Abstract
Subway tunnel of Nanchang may pass through one or several weathered argillaceous siltstone in the construction process. To reveal the influence of weathered argillaceous siltstone on the long-term settlement of subway tunnel, the dynamic triaxial tests of intensely and moderately weathered argillaceous siltstone were carried out. Based on these tests results, the evolution law of cumulative plastic dynamic strain was analyzed and a prediction model of cumulative plastic strain was established. Finally, an actual subway tunnel with weathered argillaceous siltstone was selected for long-term settlement prediction analysis. The prediction data shows that the sedimentation value of tunnel is approximately 20.87 mm under 100 years operation. Research results indicate that the dynamic strain of weathered argillaceous siltstone under cyclic vibration load is mainly affected by dynamic stress and static deviatoric stress. When the static deviatoric stress increased from 0 kPa to 200 kPa, the dynamic strain of intensely and moderately weathered argillaceous siltstone increased by 8.53 times and 5.97 times, respectively. Therefore, the intensely weathered argillaceous siltstone (IWAS) is more susceptible to static deviatoric stress than moderately weathered argillaceous siltstone (MWAS). In addition, increasing the confining pressure will accelerate the expansion of fissures in intensely weathered argillaceous siltstone, while the fissures in moderately weathered argillaceous siltstone will be inhibited, which show diametrically opposite results.
Yu-Feng Shi, Chao Yu, Xiang-Sheng Chen, Xiu-Shao Zhao, Bi-Tang Zhu
Tunnel Reinforcement in Soft Grounds Using Umbrella Arch Method
Abstract
The efficient use of underground spaces through constructed tunnels offers a practical solution for the recent increase in the mobility demands. However, in the case of tunneling at shallow depths that the ground consists of weak soils, it deems necessary to deploy reinforcement techniques in order to maintain the stability and safety of the construction process. In this study, the influence of the Umbrella Arch Method (UAM) on controlling the tunneling-induced settlements under severe geotechnical conditions was assessed. To accomplish this objective, the tunnel excavation sequences, as well as the UAM deployment, were simulated through a series of finite element numerical modeling, considering the in-situ conditions associated with a case study. Post-processing of the numerical modeling results indicated that using the UAM resulted in a substantial reduction in the corresponding tunnel crown and ground surface settlements. Additionally, through a parametric analysis, design parameters of UAM pipes, in terms of geometrical and installation- related properties, were evaluated to provide relevant information on the optimized values for each individual parameter. The associated results showed that the optimum value of the pipe length is approximately 1.5 Dtunnel (the equivalent tunnel diameter). Additionally, for the range of design parameters evaluated in this study, the best performance of the UAM was achieved when the pipes diameter, length, installation angle, and installation distance were in the neighborhood of 12 cm, 12 m, 6°, and 30 cm, respectively.
Ali Morovatdar, Massoud Palassi, Kambiz Behnia
Influence Factors of the Adhesion Strength of Clayey Soil
Abstract
When earth pressure balance (EPB) shield tunnels are constructed through clayey ground, the soil adheres to the cutter and cutterhead due to the high adhesion strength between the steel and the clay. To investigate the influence of different factors on the adhesion strength, this study used montmorillonite, kaolin and mixtures of the two as test soils. The adhesion strength between steel and clay was determined with a customized rotary shear apparatus. The results show that the adhesion strength between the steel and the clay increased with the consistency index. As the consistency index decreased, the effect of the normal pressure on the adhesion strength gradually weakened. As the contact angle of the shear plate increased, the adhesion strength decreased. The plasticity index had little effect on the adhesion strengths. The adhesion strength increased gradually with increasing surface roughness. The most important factors which influenced the adhesion strength are the soil consistency index, the normal pressure and the contact angle of the shear plate.
Shuying Wang, Pengfei Liu, Jiazheng Zhong
Numerical Investigation on Cracking Behavior of Shield Tunnel Lining Subjected to Surface Loading: A Parametric Study
Abstract
An optimized finite element method (FEM) based on layer structure method has been put forward, which combined the nonlinear behavior of both the structure and the soil surrounding. The lining is simulated with solid element and meshed finely, while the longitudinal joint between segments is modeled by 6-node line interface element. Nonlinear mechanical behaviors of soil, concrete, reinforcement and interfaces are considered with advanced material models. A parameter study is conducted to reveal the influence of several concerning parameters such as the rotation angle of the ring, the width of surface loading, the offset of surface loading and the depth of the tunnel. To better illustrate the result, several indexes including maximum crack width, crack index and crack ratio is introduced to evaluate and forecast crack behavior. The results show that the crack-resistant ability of the tunnel is slightly enhanced as the rotation angle of the ring increases. A more unfavorable influence can be brought to linings by the shift of the surface loading when its offsetting is smaller than 30 m in the case. However, the influence on segment cracking caused by the change of the tunnel depth is complicated when stress redistribution after tunnel excavation is considered, and there is an unfavorable buried depth when the crack ratio reaches maximum. Finally, a simple fitting equation, which is based on the previously mentioned numerical simulation, is provided to establish the relationship between the horizontal ovalisation and the crack ratio.
Jiachong Xie, Jinchang Wang, Weiming Huang, Zhongxuan Yang, Rongqiao Xu
The Freezing Characteristic Curve of a Coarse-Grained Volcanic Soil
Abstract
Volcanic soils are widely distributed in the Hokkaido prefecture of Japan, where seasonal freezing and thawing occur. In frozen soils, a portion of pore water remains unfrozen, due to the effects of capillarity, adsorption, and possibly solute. The variation of the amount of unfrozen water in a frozen soil, which is primarily influenced by subzero temperature, has great impacts on the physical and mechanical behavior of the soil. In the present study, the soil-freezing characteristic curve (SFCC) of a typical volcanic soil sampled in Hokkaido, namely, the Komaoka soil, was investigated. The unfrozen water content of the prepared Komaoka soil specimens was measured using a cheap and convenient moisture sensor. The temperature of the specimens was determined by a rugged temperature sensor. Different number of freeze-thaw (F-T) cycles, and different freezing/thawing methods (i.e. one- and three-dimensional) were considered, and their effects on the SFCC were investigated. The experimental results suggest that neither of the F-T cycles nor the freezing/thawing methods had significant influence on the measured SFCC. The present study can contribute to understanding the freezing characteristic of the investigated soil in specific and that of other cold region soils in general.
Junping Ren, Shoulong Zhang, Tatsuya Ishikawa, Sai K. Vanapalli
Structural Characterization of Residual Soil and the Effect of Drying and Wetting Cycles on Its Strength
Abstract
A series of indoor tests was performed to obtain the physical and mechanical properties and structural characterization of granite residual soil. Experimental results indicated that clot and flocculation are the primary forms of microstructure, and the residual appearance of the parent rock’s crystal pattern is reserved. Structural strength is provided by strong cementation and residual chemical bond force. The clay mineral is mostly kaolin, which exhibits a laminated structure. The grain particle of granite residual soil presents the mixed features of sand and clay. The coefficient of compressibility is mostly distributed with in the range of 0.30–0.35 MPa−1, which is for medium compressible soil. Granite residual soil demonstrates good mechanical performance even under saturation condition. However, strength variability is notable. Drying and wetting cycles reduce the strength of granite residual soil, and strength decreases by approximately 30% after two drying and wetting cycles.
Wei Bai, Lingwei Kong, Liming Xu, Xianwei Zhang, Zhiliang Sun, Ran An, Xiu Yue
Analysis of Tunnel Face Stability of Shield Tunneling Through Water-Rich Sand-Pebble Stratum
Abstract
The sand and pebble stratum generally exists in the urban underground engineering construction. When disturbed by the outside world, especially under the condition of rich water, it is easy to cause stratum loss due to the characteristics of sand pebble stratum, resulting in instability of the face and surface settlement and other problems. In this paper, the physical and mechanical parameters of sand pebble soil in a subway area of Changsha were obtained through laboratory tests, and then the micro parameters were calibrated. According to the calibrated micro parameters, a PFC3D full scale model considering seepage was established for the stability analysis of the tunnel face. Through the analysis of the numerical simulation results, the influence of different factors such as stress ratio, buried depth (C), shield diameter (D), and boulders on the stability of the tunnel face was obtained, and the variation characteristics of the limit support pressure and the critical stress ratio of the instability index were obtained under different conditions. The results show that the formation stability increases with the increase of stress ratio in the process of shield tunneling. When the stress ratio is less than the critical stress ratio, the tunnel face will be unstable. When the boulder is broken, the instantaneous velocity of the particle in the center of the tunnel surface can reach 3m/s, and the risk of instability of the tunnel surface is increased. The pressure of the limit support increases with the increase of the buried depth. When C/D = 3, the pressure of the limit support tends to be stable. The critical stress ratio decreases with the increase of C/D, and the lower the critical stress ratio is, the stronger the self-stabilizing ability of the tunnel surface is.
Wei Wang, Fan Liu, Zhao Han, Xinyuan Zhang, Xu Zhou
The Influence of Recycled Power Dust on Asphalt Mixture
Abstract
Laboratory tests aimed at investigating compaction properties, volumetric characteristics, and mechanical performance of the bituminous mixtures. The results suggest that recycled powder dust is suitable to be used in bituminous mixtures, also, in certain conditions, the investigated recycled powder dust increases the performance of the corresponding mixtures in comparison to mineral filler. For AC-20C asphalt mixture, when the ratio of the recycled powder dust substitution is below 50%, the water stability and low temperature stability of the mixture meet the specification requirements. When the ratio of the substitution exceeds 75%, the mixture is found prone to rutting. It is recommended to use the recycled powder dust in medium and light traffic conditions.
Qingqing Zhang, Lingyu Meng, Jinyan Liu
Backmatter
Metadaten
Titel
Advances in Innovative Geotechnical Engineering
herausgegeben von
Prof. Yong Liu
Ph.D. Sabatino Cuomo
Ph.D. Junsheng Yang
Copyright-Jahr
2021
Electronic ISBN
978-3-030-80316-2
Print ISBN
978-3-030-80315-5
DOI
https://doi.org/10.1007/978-3-030-80316-2