岩土工程技术

Limit Equilibrium Method for Reinforced Slope Based on Horizontal Slice

FAN Pengxian, CHEN Canshou, HUANG Yu

2010, 24(2): 55-57,97. doi: 10.3969/j.issn.1007-2993.2010.02.001

[Abstract](48) [PDF 234KB](7)

Abstract:
Reinforced soil is a new economical and dependable method of slope reinforcement. Aimed at problems new type reinforced soil slope brought and the shortage of limit equilibrium method based on vertical slice, a rigorous approach based on horizontal slice for limit equilibrium analysis method is presented, in which the reinforcement force was assumed horizontal and failing at its maximum tensile strength. Limit equilibrium method based on horizontal slice divide slide body into horizontal slices, regards the resistance of reinforced material as additional outer forces, and then apply assumptions of limit equilibrium method to analyze forces acting on slices. Status of typical slice is analyzed, and implicit expression is derived by utilize of force equilibrium. The coefficient of interslice force is solved through moment equilibrium, and ultimately the real safety factor is approached iteratively. Bearing capacity of slope is also studied. Case study shows that the result of the method presented is a little bigger than classic limit equilibrium method.

Analysis for Monitoring Results of Vacuum Preloading on Vietnam Ca Mau Fertilizer Project

GAN Qiling

2010, 24(2): 58-61. doi: 10.3969/j.issn.1007-2993.2010.02.002

[Abstract](31) [PDF 211KB](5)

Abstract:
Vacuum preloading method is adopted in soft clay treatment of the design for Vietnam Ca Mau Fertilizer Project. Some monitoring methods is adopted in course of vacuum preloading, such as vacuum degree under membrane, ground settlement, layered settlement, groundwater level, pore water pressure and deep horizontal displacement. Monitoring objectives and methods are introduced. The final settlement under preloading and consolidation degree in every stage are also been calculated. Evidences for unloading are provided.

Computation of Frame Supporting Structure With Pre-stressed Anchor Bars Based on Force Transfer

HU Mingjun, LAI Yong

2010, 24(2): 62-66. doi: 10.3969/j.issn.1007-2993.2010.02.003

[Abstract](29) [PDF 312KB](9)

Abstract:
Through the computation of bulkhead with classical theory of Timoshenko, it was found that the moment on bulkhead was large, and the moment was transferred to the beams. This article deduced a model with force transfer, it could better worked on the force computation of the structure. With C++ BUILDER program, linking with real instance, a computaring software was developed. As the result showed, the theory of this paper was reasonable.

Numerical Analysis of Improved Vertical Slices Method for Circle Slip Slope

LIU Zizhen

2010, 24(2): 67-70,74. doi: 10.3969/j.issn.1007-2993.2010.02.004

[Abstract](39) [PDF 293KB](7)

Abstract:
Combination traditional limit equilibrium methods and modern limit equilibrium methods, the vertical slices method is used for the slope stability analysis with circle slip surface. By the generalized internal forces between the vertical slices, an improved slices method based on circle slip surface is proposed. Through establishing the mechanics calculation formula for the circle slip slope surface, the relationship between influence coefficient of generalized internal forces and safety factor is can be brought forward, using the numerical calculation and iterative process, the slope safety factor with the changed influence factor of the internal forces can be obtained under the balanced force and balanced torque respectively. It can describe the slope stability quantitatively. The result shows that the improved vertical slices method for circle slip slope reflects the interaction between circle slip surface and vertical surface. The numerical calculation is easy with a higher accuracy.

Some Problems of Geotechnical Engineering Practice

ZHANG Haidong, WANG Wenliang, MA Zhuang

2010, 24(2): 71-74. doi: 10.3969/j.issn.1007-2993.2010.02.005

[Abstract](24) [PDF 276KB](7)

Abstract:
In geotechnical engineering practice, it is often met some paradoxical questions. For example, engineering properties of the matching index, checking weak interlayer and calculation of composite modulus. For these issues, different understanding of the concepts clue to different conclusions, and sometimes even wrong conclusions. In this paper, we will do some research on geotechnical engineering problems, which encountered in practice, and we also want to do some contributions to attracting valuable opinions.

Investigation on Distribution or Saline Soil and Its Unique Engineering Properties in Qinghai

LUO Youdi

2010, 24(2): 75-78,83. doi: 10.3969/j.issn.1007-2993.2010.02.006

[Abstract](49) [PDF 368KB](6)

Abstract:
Saline soil is universal in many parts of Qinghai, when sodium sulfate content less than 1% the saline soil will also have salt bulge; and ultra-chloro-saline soil subsidence will not dissolved. With in-depth and detailed demonstration and research. Based on the facts obtained with the existing theoretical and normativeis inconsistent with the argument

The Application of the 3D Laser Scanning Technology in Geological Catalog

ZHOU Feng, SHI Yi, TANG Qiuyuan

2010, 24(2): 79-83. doi: 10.3969/j.issn.1007-2993.2010.02.007

[Abstract](41) [PDF 465KB](9)

Abstract:
The applications of the 3D laser scanning technology in geological logging, changed the model of geological logging what is called "the ruler+ the compass" in traditional, and at the same time, the technology is seized of the unique advan-tages such as high efficiency, high precision and high benefit . The paper makes a simple introduce with the principium of the technology, and combining with the example of a project, discussion the methods of how the 3D laser scanning technology get the geoinformation and how to translate the information into useful things, and to assess the rock quality of the geological logging region, demonstrated the practicality and the effectiveness of the 3D laser scanning technology in geological catalog, fully demonstrating the technology has a bright future in the geological application.

The Compositive Detection Optimization Assessment of the Treatment Project Using Grouting in the Mined Out Area Beneath the Highway

SHI Diansheng, JIA Xuemin, WANG Kejia

2010, 24(2): 84-88. doi: 10.3969/j.issn.1007-2993.2010.02.008

[Abstract](33) [PDF 357KB](6)

Abstract:
A number of methods have been used to evaluate results derived from the treatment project in mined out area though most of them is not certain with accurate and confirmed results at present. And there were no reliable code or regulation as well any criteria to follow in highway construction. In the paper, based on surveillances and instruments to evaluate the results of the treatment project using grouting in the typical mined out area beneath the highway in China, a system to evaluate results of the treatment is discussed and some criteria are proposed. Principle, methods and synthetic procedure for trying to test results of the treatment project in a mined out area were confirmed. Also, a results derived from the numerical analogy are discussed as a methods to evaluate results of the treatment project in the mined out area. It shows a picture for the further researches to evaluate results of the treatment project in the mined out area in future.

Stability Analysis of Slope in Hancheng Coal Mine Base on Strength-Reduction Method

WANG Yu, TIAN Hao, YU Hongming

2010, 24(2): 89-93. doi: 10.3969/j.issn.1007-2993.2010.02.009

[Abstract](57) [PDF 403KB](7)

Abstract:
The finite element c-tanФ reduction theory is applied to the slope stability analysis, which is using ANSYS finite element analysis software, based on Drucker-Prager yield criterion, using force and displacement convergence criteria as the damage criterion to carry out the slope stability analysis. When the reduction coefficient reaches to a certain value, the non-linear finite element calculation will not converge, the displacement of the sliding surface will mutation, slope, within a certain amplitude of the generalized shear strain gradient from its base to the top, so the slope had been destroyed, the previous reduction factor shall be the stability factor. In the paper, taking the Hancheng coal jointed rock slope for example, applying the c-tanФ, reduction theory to its stability analysis. The results show that the FEM and strength - reduction method is more convenient and reasonable in the analysis of rock slope stability. It can reflect the actual slope state, and give stability factors that are closer to the actual ones.

The Comprehensive Analysis of Large Diameter Pile Compression and Side Friction

JIAO Lei, GUO Zhongxian, MA Liang

2010, 24(2): 94-97. doi: 10.3969/j.issn.1007-2993.2010.02.010

[Abstract](54) [PDF 266KB](10)

Abstract:
In order to analyze the pile compression and lateral friction impact on the bearing capacity of large-diameter pile and obtain the stress-strain values of the pile which are situated at the interface of soil layers under all levels of the loads, a great in-site static pile test is carried. We can calculate per meter of the pile compression and side friction between different layers. The test results show that between different layers the pile side frictions ratios of measured value to surveyed value are radically different, the ratios of upper parts are smaller and the lower parts are larger. There are few changes of the pile side friction on the upper parts but the lower parts increase by stages. The compression is a physical quantity which reflects the working characters of the material. Although the pile side friction's ratios of upper parts are larger, the pile compression is small. As a result the pile side friction still has the development potential and its limit value can be estimated. The bearing capacity of the large diameter pile are mainly produced by side friction, therefore, based on a comprehensive analysis of pile compression and side friction, this paper hopes to supply the valuable reference for determining the bearing capacity of the large diameter pile in Shijiazhuang Region and even in Hebei Province.

The Foundation Treatment Design of the Building on the Saline Soil

MIAO Aimei, CHEN Kang

2010, 24(2): 98-100. doi: 10.3969/j.issn.1007-2993.2010.02.011

[Abstract](26) [PDF 203KB](8)

Abstract:
This article describes the foundation treatment design of the high-rise buildings on the Saline Soil, the construction of the drilling compaction Pile and the treatment results. Atlast,We analyse several issues of the design and construction for the saline soil.

Risk Management for Construction of Chating Station Foundation Pit of Nanjing Metro Line Two

WANG Derong, LI Wenpei, ZHOU Bin

2010, 24(2): 101-104,109. doi: 10.3969/j.issn.1007-2993.2010.02.012

[Abstract](25) [PDF 312KB](5)

Abstract:
Along with the development of Chinese urbanization, the pressure of ground transportation in the city enlarges increasingly, the fast development of underground track projects is of necessity. Since the influence of geological condition and surrounding envirornment on the engineering construction, risks of underground construction is more complicated than that of ground engineering. In order to avoid the huge loss caused by the construction accident, it is very necessary to carry on the risk management. Combined with foundation pit project of chating station of Nanjing metro line two, the risk identification of subway station foundation pit is presented. Based on the risk identification, the analysis and evaluation of risk is carried on by using the matrix method of risk evaluation, and the grade of various risk factor is determined. And combine practice experience of construction, expert analysis and correlative theories, corresponding prevent and control measures is put forward for the risk in construction of metro station foundation pit project.

The Deep Horizontal Displacement Test and Analysis About Undisturbed Structure of One Deep Pit in Shanghai

LIN Lixiang

2010, 24(2): 105-109. doi: 10.3969/j.issn.1007-2993.2010.02.013

[Abstract](38) [PDF 326KB](11)

Abstract:
In the deep foundation excavation process,, the undisturbed structure will produce the horizontal displacement for the pit due to lateral soil pressure, when the undisturbed horizontal displacement is too large, the whole supporting system will be instability or destruction, so the deep horizontal displacement testing of the deep foundation pit structure is particularly important. In this paper, it is analyzed that the horizontal displacement testing results of a deep foundation in shanghai, which include the displacement rate, the time effect of different excavation conditions, the different displacement reasons in the undisturbed edges and the comparison between the maximum displacement in end monitoring and the calculated displacement values, and in the end, it is proposed that some relevant measures to control this deformation.

2010 Vol. 24, No. 2