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2019 | Buch

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Controlling Differential Settlement of Highway Soft Soil Subgrade

A New Method and Its Engineering Applications

verfasst von: Hanhua Zhu, Zhijun Wu, Mengchong Chen, Yongli Zhao

Verlag: Springer Singapore

Buchreihe : SpringerBriefs in Applied Sciences and Technology

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik" , Springer Professional "Wirtschaft"

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Über dieses Buch

Drawing on years of practical on-site experience, this book presents a new method for controlling "bridge-head bumping" in soft soil ground. Based on deformation compatibility and control theory of structure, it proposes strategies for improving the design method of soft soil ground and the effective "bridge-head bumping" control method. Soft soil ground is chiefly characterized by a large void ratio, high compressibility, high water content, low impermeability, low strength, strong structure and high sensitivity. As a result, it has pronounced rheological properties, and controlling "bridge-head bumping" in soft soil ground is essential to control the amount of soil rheology-induced unstable successive settlement. The book offers extensive information on this and related topics, making it a valuable guide for engineers in Civil Engineering and Geotechnical Engineering alike.

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Inhaltsverzeichnis

Frontmatter

Improved Design Method of Highway Soft Soil Subgrade

Frontmatter

Chapter 1. Analysis of Differential Settlement of Highway Soft Soil Subgrade

Abstract

The soft soil subgrade has the characteristics of large pore ratio, high compressibility, high water content, low permeability, low strength, strong rheological property, strong structural property, and high sensitivity, allowing it to easily lead to differential settlement of subgrade. The core problem is the inconsistency of the designed analysis model (Fig. 1.1a) of highway soft soil subgrade and actual stress and deformation state of soft soil slag road subgrade (Fig. 1.1b, c).

Hanhua Zhu, Zhijun Wu, Mengchong Chen, Yongli Zhao

Chapter 2. Overview of Methods for Treating the Differential Settlement of the Soft Soil Highway Subgrade (Including the Bumps at Bridgeheads)

Abstract

With the rapid construction of highways in China since the 1990s, methods for treating the differential settlement of the soft soil highway subgrade (including the bumps at bridgeheads) have gradually been developed.

Hanhua Zhu, Zhijun Wu, Mengchong Chen, Yongli Zhao

Chapter 3. Inspirations from the Stability of Ancient Structures

Abstract

India’s Jaisalmer Sandcastle is a desert castle with a history of more than 800 years. With the development of the tourism industry, many inns, hotels and entertainment venues have been built in the castle, and residents can enjoy convenient tap water.

Hanhua Zhu, Zhijun Wu, Mengchong Chen, Yongli Zhao

Chapter 4. Explorations of the Reasonable Structure of the Soft Soil Highway Subgrade and Solutions

Abstract

The traditional “apple falling site prediction” (the apple issue) and “leaf falling site prediction” (the leaf issue) are governed by the same prediction theory. However, the actual prediction methods differ; the simplest approach is to adopt the method used by man (childhood, adulthood, and old age) for maintaining motion stability to resolve the “leaf issue”.

Hanhua Zhu, Zhijun Wu, Mengchong Chen, Yongli Zhao

Chapter 5. Comparative Test, Calculation, and Analysis Concerning the Stability and Looseness of the Soft Soil Highway Subgrade

Abstract

Given different subgrade structures, the loose subgrade of No. 1 highway and the stable subgrade of No. 2 highway were drilled to obtain cores. Both No. 1 highway and No. 2 highway are located within the same soft soil area and are not located far away from each other.

Hanhua Zhu, Zhijun Wu, Mengchong Chen, Yongli Zhao

Chapter 6. Comparative Test and Study of the Strength and Rheological Property of the Soft Soil Subgrade

Abstract

During preparation of the samples of No. 1 and No. 2 highways’ soft soil subgrades, great effort has been made to reduce the disturbance caused to soil, to ensure that the mechanical property of indoor soil was consistent with the actual situation, as shown in Fig. (6.1) [1‐3].

Hanhua Zhu, Zhijun Wu, Mengchong Chen, Yongli Zhao

Chapter 7. Basic Characteristics of the Soft Soil Highway Subgrade and Its Design Method

Abstract

The results of structural comparison between No. 1 highway and No. 2 highway are obtained according to the studies in the previous sections, as shown in Table 7.1 and Fig. 7.1 [1‐4].

Hanhua Zhu, Zhijun Wu, Mengchong Chen, Yongli Zhao

Chapter 8. Practical Design Method for the Soft Soil Highway Subgrade

Abstract

The soft soil highway subgrade involves the issue of plane strain, its mechanics characteristics conform to the assumptions of the Terzaghi theory; it requires control of the stability of the state of the soft soil highway subgrade’s forced deformation; and the adoption of a synthetic method to cope with the differential settlement of the soft soil highway is necessary.

Hanhua Zhu, Zhijun Wu, Mengchong Chen, Yongli Zhao

Practice in the Improved Design Engineering Construction of the Soft Soil Highway Subgrade

Frontmatter

Chapter 9. Practice in the Construction of the Lime-Treated Soil Highway Subgrades in Jiaxing City

Abstract

(1) The soil–stone slag mixture construction control has difficulty in satisfying the requirements, which may easily cause differential settlement in highway during service. The lime-treated soil particles are uniform, and a plate body structure can form after construction. (2) The water stability of the soil–stone slag mixture is low, water can easily permeate the subgrade, which induces an adverse impact. The water stability of the lime-treated soil is high; the resulting plate body structure exhibits a certain water-resisting property. (3) The exploitation of the soil–stone slag mixture causes severe damage to the local ecological environment. From 2013, the government shut down numerous quarries, leading to shortage of soil–stone slag mixtures. The lime-treated soil can be easily obtained from the plain areas in Zhejiang Province, such as the waste soil from hydraulic reclamation in the Qiantang River, canal dredging, drilling in overpass construction, can be utilized. A comparison between the soil–stone slag mixture subgrade and the lime-treated soil subgrade in Jiaxing City is provided in Table (9.1).

Hanhua Zhu, Zhijun Wu, Mengchong Chen, Yongli Zhao

Chapter 10. Practice in Treatment of the Bumps at Bridgeheads on the Existing Highway in Taizhou City

Abstract

The foam bead concrete consists of foam beads (EPS particles), medium-coarse sand, macadam, cement, and water at a certain designed mix proportion through blending. All materials used in the tests are chosen and obtained nearby. The foam beads (EPS particles) are polystyrene spherical particles with a diameter of 3–5 mm and an apparent density of 5–20 kg/m³. The cement is ordinary Portland cement PO32.5. For the aggregate, the sand fineness modulus in the fine aggregate ranges from 3.0 to 2.3. The size distribution of macadam particles in the coarse aggregate ranges from 5 to 21.5 mm. The admixtures consist of common early-strength water-reducing agents, microsilica and fly ash.

Hanhua Zhu, Zhijun Wu, Mengchong Chen, Yongli Zhao

Chapter 11. Practice in Treatment of the Bumps at Bridgeheads on the Highways in Wenzhou City

Abstract

With a total length of 10 km, the Ouhai section of National Highway 104 in Wenzhou is a typical soft soil section. After this section was opened to traffic after reconstruction in 2000, the differential settlement developed in the soft soil subgrade, causing very severe bumps at the bridgeheads. The average daily mixed traffic volume at this section ranges from 50,000 to 60,000 vehicles. This section has 13 bridges. The bridgeheads need to be paved each year. To effectively solve the bumps at bridgeheads, in 2008, Xiacheng No. 2 Bridge was chosen as the test project, in which four different methods were adopted to treat the corresponding four bridgeheads.

Hanhua Zhu, Zhijun Wu, Mengchong Chen, Yongli Zhao

Chapter 12. Practice in Treatment of the Bumps at Bridgeheads of the Highways in Ningbo City

Abstract

The highway alteration project of the section from Meilin to Shanheling in Ninghai urban areas involves a line with a total length of 11.235 km. The section is designed according to the standard for the first-class highway with 4–6 lanes; the design speed is 80 km/h; and the subgrade width is 26.5–45 m. The transportation of earthwork is restricted during highway excavation in urban areas. In addition, the outsourced fillers are also prohibited due to the difficulty in transportation. Therefore, it is more appropriate to use the undisturbed soil to carry out the construction after the undisturbed soil is treated by lime. Specific judgment can be made from an economical and environmental protection perspective, as shown in Tables 12.1 and 12.2.

Hanhua Zhu, Zhijun Wu, Mengchong Chen, Yongli Zhao

Backmatter

Titel: Controlling Differential Settlement of Highway Soft Soil Subgrade
verfasst von: Hanhua Zhu
Zhijun Wu
Mengchong Chen
Yongli Zhao
Copyright-Jahr: 2019
Verlag: Springer Singapore
Electronic ISBN: 978-981-13-0722-5
Print ISBN: 978-981-13-0721-8
DOI: https://doi.org/10.1007/978-981-13-0722-5