岩土工程技术

The Value of the Geotechnical Engineering Cases

Gu Baohe

2015, 29(6): 271-272,279. doi: 10.3969/j.issn.1007-2993.2015.06.001

[Abstract](55) [PDF 581KB](17)

Abstract:
The value of geotechnical engineering cases namely typical cases in geotechnical engineering mainly lies in three aspects.First,geotechnical engineering cases are a model of success and failure warning.Second,they are the same proportion of scientific experiments,because the calculation can not be completely accurate,only prototype measurement is quantitative Third,they are the source of new concepts and new methods.Demonstrate with actual examples.And it is pointed out that:cases provide a fresh and vivid teaching material;cases are a treasure trove of gathered both positive and negative experience;cases are the source of revision of standards and specifications;cases are the foundation of the innovation theory and technology.

Discussion on Accident of Foundation Excavation of Xianghu Station of Hangzhou Subway No.1 Line Again

Li Guangxin

2015, 29(6): 273-279. doi: 10.3969/j.issn.1007-2993.2015.06.002

[Abstract](45) [PDF 5000KB](20)

Abstract:
In the paper,some discussions on accident of foundation excavation of Xianghu Station of Hangzhou subway No.1 line are proposed from construction,design and management.Some questions are proposed about codas concerned with building foundation excavation and its applications.It is indicated that constructors have important blame in the accident.In the design of the engineering,there are mistakes.For example,in analyses of stability against overturning of retaining structure,overall stability by Swedish circle method and stability against heaving of pit bottom,if the CU shear strength parameters of saturated clay are adopted,the resistant force has to be calculated by buoyant unit weight rather than by saturated unit weight of soil.The high sensitive of clay is not paid enough attention.It is an important fault that the Fengqing road is not closed during the construction.

The Urban Rail Transit Typical Engineering Geological Problems Analysis and Countermeasures

Gao Wenxin, Huang Suhang, Xie Feng

2015, 29(6): 280-284,305. doi: 10.3969/j.issn.1007-2993.2015.06.003

[Abstract](41) [PDF 2361KB](16)

Abstract:
The urban geological condition and genesis in current domestic rail transit are summarized and differentiated in the article.The typical engineering geological problems in the construction of the urban rail transit are summarized and analyzed and corresponding engineering geological risk controlled countermeasures are also raised.The result of research provides direction and reference in urban rail transit construction in different geological regions.

Review of Ground Treatment Techniques and Their New Progresses

Hua Jianxin, Yan Degang, Zhao Jiewei, Guo Miwen

2015, 29(6): 285-300. doi: 10.3969/j.issn.1007-2993.2015.06.004

[Abstract](47) [PDF 2672KB](18)

Abstract:
This paper reviewed on ground treatment techniques in China,introduced their new progress.Furthermore,it also probed into the existing problems of foundation treatment,provided some directions which should be strengthened in the future research.

The Application of Magnetic Gradient Test in Ningbo Rail Transit Project Construction

Zhang Chunjin, Ye Ronghua

2015, 29(6): 301-305. doi: 10.3969/j.issn.1007-2993.2015.06.005

[Abstract](55) [PDF 1072KB](10)

Abstract:
This paper introduces the method of combining magnetic gradients test and direct detecting to detect the deep buried metallic pipeline First,using the magnetic gradient test to detect the location,trend and depth of the deep buried metallic pipeline roughly.Then,locate the deep underground pipeline accurately by using the direct detecting.Combined with Ningbo rail transit project,this method is proved to be effective in application.

Analysis of Bearing Characteristics of Single Pile Based on the Axial Force Distribution Function

Liang Jinguo, Ding Jihui, Liu Hongchao

2015, 29(6): 306-310,323. doi: 10.3969/j.issn.1007-2993.2015.06.006

[Abstract](61) [PDF 1289KB](10)

Abstract:
Based on the attenuation law of the pile axial force with the buried depth of piles under the vertical load,the expression of the axial force distribution function of pile section is proposed and is related to the ratio of the length to diameter ratio of the pile and the Share ratio of the tip.The bearing characteristics,law of load transfer of the pile body,the distribution law of axial force and pile side resistance of the Cast-in-place pile under vertical load are analyzed by the application of the axial force distribution function.The comparison of the measured and calculated results shows that the axial force of the pile section is consistent with the measured results by the axial force distribution function of the pile section,the distribution law of the pile side resistance,the total side resistance and the total tip resistance based on the pile axial force distribution function different load level are consistent with the measured results.

Finite Element Analysis of Hoisting Engineering Influence on Pile Foundation

Zhou Chen, Wang Jian, Li Baoqiang

2015, 29(6): 311-315. doi: 10.3969/j.issn.1007-2993.2015.06.007

[Abstract](48) [PDF 1200KB](10)

Abstract:
In the engineering hoisting construction process,the use of crane machinery will produce different effects on nearby crane dock and the operation process of the machinery,which will produce certain change of stress and displacement of pile foundation.This paper studied the influence on pile foundation in mechanical lifting process of the dock and the movement through the analysis of an actual project.With the comprehensive analysis of displacement and stress,influence of hoisting machinery foundation analysis was studied using the finite element method,which is helpful to assess the feasibility of the construction machinery operation.

Application of Electric Prospecting in Karst Exploration

Nie Xijiang, Cui Liang, Chen Runqiao

2015, 29(6): 316-319. doi: 10.3969/j.issn.1007-2993.2015.06.008

[Abstract](47) [PDF 826KB](12)

Abstract:
The karst area of China is extensive,almost 30%of the land area.For highways,bridges,dams and other projects,in the site,find out the underground karst or other mining area cave is very important,because they will directly affect the quality and safety of project.In these areas,the geological condition is very complex,to understand the working area of the natural geographical and geological conditions as detailed as possible,can benefit in measuring line of reasonable arrangement and observation system design for the optimization,and initially determine the problems existing in the construction process,to formulate corresponding measures to ensure the high quality of the data acquisition.With a railway as an example,first introduced the theoretical knowledge of electrical prospecting,and related the electrical sounding in the cave exploration in the area of data acquisition,processing and interpretation,to clarify the important application of electrical sounding in the karst exploration.

Division Method of Changchun Cretaceous Mudstones Weathering Degree

Li Xueying, Sun Guang, Gao Tao

2015, 29(6): 320-323. doi: 10.3969/j.issn.1007-2993.2015.06.009

[Abstract](55) [PDF 712KB](13)

Abstract:
Changchun is underlain by Cretaceous mudstone,belong to the extreme soft rock or soft rock,has the characteristics of softening and disintegration.At present,some construction projects need to use Changchun deep mudstone as pile foundation bearing layer.This kind of rock,national standard "Code for Investigation of Geotechnical Engineering" cannot think of the weathering degree of division,this view is contrary to Changchun engineering construction and engineering experience.Jilin landmark "Geotechnical Engineering Investigation Technology Interim Provisions" of the standard penetration test of mudstone weathered state,gives the whole weathered to medium weathering mudstone criteria,but the influence factors of the standard penetration test is many,so this method is not suitable for deep mudstone.This paper uses the method of shear wave velocity test,proposes the division standard of weathering degree of the Changchun mudstone,especially solves the deep mudstone weathering degree division problems.By the engineering test,the effect is good.

2015 Vol. 29, No. 6