岩土工程技术

Singh-Mitchell Creep Model and Grey Prediction on Tianjin Marine Soft Soil

Yang Aiwu, Zhang Jingxian, Lu Liqiang

2010, 24(4): 163-165,175. doi: 10.3969/j.issn.1007-2993.2010.04.001

[Abstract](52) [PDF 716KB](5)

Abstract:
Through unconsolidated undrained triaxial creep test, established Tianjin marine soft soil Singh-Mitchell creep model, simultaneously used the measured data to carry on the gray forecast. The test result indicated that: the Singh-Mitchell experience model can predict creep of Tianjin marine soft soil, using measured data can also carry on the short-term grey prediction of Tianjin marine soft soil, the effect is good,which can take the reference for the project practice.

A New Method of Calculating the Bearing Capacity of Strip Foundation

Zhang Qinxi, Li Jihong

2010, 24(4): 166-170. doi: 10.3969/j.issn.1007-2993.2010.04.002

[Abstract](21) [PDF 763KB](7)

Abstract:
Based on strip foundation and assuming the sliding surface is circle,which is closer to reality, the author deduced a new theory formula for calculating the bearing capacity of strip foundation. And it was taken to compare with several existing calculation methods of foundation bearing capacity to evaluate it the legitimacy and applicability of engineering practice.

Seepage Stability Analysis on the Dyke Through by Trenchless Pipeline

Zhou Xianjin, Deng Zhengdong

2010, 24(4): 171-175. doi: 10.3969/j.issn.1007-2993.2010.04.003

[Abstract](41) [PDF 735KB](4)

Abstract:
A covert and curving zone,which is disturbed by trenchless pipeline engineering,is formed under the river and dyke stratum. Based on an actual engineering, a corresponding groundwater simulation model is proposed for evaluating the possibility of seepage failure induced by the disturbed zone Under the extremely unfavorable hydmlogy-weather conditions,the maximum groundwater flow gradient is estimated by the simulation model. Then, the possibility of seepage failure induced by engineeng can be quantitatively analyzed based on the critical hydraulic gradient method. The result shows that the maximum groundwater flow gradient is increasing gradually and its acceleration is decreasing corresponding to increasing river level. The maximum groundwater flow gradient is influenced obviously by the thin and low-permeability silt layer of river bed.

The Analysis for Lattice Beam Tied by Pre-stressed Anchor Ropes Based on the Coupling of Compatible Deformation Between Structure and Slope

Zong Quanbing

2010, 24(4): 176-179. doi: 10.3969/j.issn.1007-2993.2010.04.004

[Abstract](30) [PDF 779KB](5)

Abstract:
There are a series of evident interaction coupling of compatible deformation between the structure and slope because of propagation effect of deformation in soil or rock mass when the reinforcement system, which is compounded by the pre-stressed anchor rope and lattice beam,is employed to strengthen a slope. The coupling effect, however, is neglected in the current procedure of analyzing based on the Winkler's spring assumption that is used in the foundation structure design widely. Now, an approach, which can consider the coupling of deformation at the base contact points each other, has been set up on the base of the elastic semi-space foundation theory for lattice beam. It is proved that the newly proposed analysis model is reasonable and practicable by comparing the multifold solutions with the tests.

GIS-Based Regional Risk Assessment of Rock Burst

Zhang Tao, He Peng, Jiang Tong

2010, 24(4): 180-183,188. doi: 10.3969/j.issn.1007-2993.2010.04.005

[Abstract](48) [PDF 752KB](4)

Abstract:
Rockburst is a prevalent phenmenon of geological disaster. How to make the rockburst's risk assessment come true by mordern technical means is a major task. Take a line DALTRO-DUKE in west line of the South-North Water Diversion Project for example, study the risk assessment base on GIS, we can get the picture of the result and analyze the accuracy and effect of the project. It is a beneficial usmy for reference to same researches according to from a whole ststem in research concepts and operation procedure of risk assessment by GIS.

Retaining Methods and General Accident Treatment of Striped-Soil Foundation Pit

Wang Zhiren, Chu Zhenhuan

2010, 24(4): 184-188. doi: 10.3969/j.issn.1007-2993.2010.04.006

[Abstract](44) [PDF 733KB](6)

Abstract:
Based on some engineering examples, the usual excavation retaining methods and theirs application conditions of striped-soil foundation pit are introduced, the general engineering accidents of striped-soil foundation pit retaining are summarized, the corresponding solution methods are provided, and the basic reason of accident is pointed out that the adjacent foundation pit backfill contains high water content and under-consolidation. It can be used as the reference for similar project.

The Processing Technology Research on the Wings Arc Fiat-type Rotary Vane Long Screw Anchor Holed Drilling Tool

Huang Xiancheng, Lin Shiwen, Ge Lianying

2010, 24(4): 189-193. doi: 10.3969/j.issn.1007-2993.2010.04.007

[Abstract](20) [PDF 708KB](5)

Abstract:
Through the problem which clay layer anchor rod drilling tool the hole appears by the past is analysised, the immediate cause of the blocking holes and the collapsed hole that the old style core drilling tool and the short screw drilling tool became in the hole proce in the horizontal direetion small angle, the soil loss of the original balance of the stress caused by drilling reduetion diameter, so that soil disturbance can not be timely output hole. Thus the long screw anchor holed drilling tool is developed, the question that holed harassed the earth output has solved, the innovation rotary vane has solved the problem of the drill hole endophragrn earth granular structure relaxation. The phenomenon that anchor rod holed has stopped up in the clay layer is settled thoroughly. The angle which anchor rod holed designs is guaranteed. A set of the comparatively standard rules that long screw anchor holed drilling tool operating forms.

Experimental Study of Soil Structure of Land-based Gravel Soil in Dynamic Compaction

Liu Yuntao, Li Lianying, Ding Yueshuang

2010, 24(4): 194-197. doi: 10.3969/j.issn.1007-2993.2010.04.008

[Abstract](36) [PDF 699KB](7)

Abstract:
The changes of the density and permeability of the Land-based gravel in the dynamic compaction researched by the bulk density test and injection test at the scene,discussed the soil structure which effected by the dynamic compaction. The results show that: dynamic compaction can improve the structure of the gravel soil, especially superficial zone, the deeper, the more unconspicuous. Under the Dynamic compaction, the changes of the soil structure is due to the grain filling in the above 3 m,and 3m the following is due to the compression of soil pore.

Experimental Study of Gradation Test

Li Yuxia

2010, 24(4): 198-201. doi: 10.3969/j.issn.1007-2993.2010.04.009

[Abstract](23) [PDF 641KB](7)

Abstract:
Gradation test is used to get the dry mass percentage of various sizes of soil particles. This is the typical test to obtain the actual soil particle size distribution curve. The curve is usually utilized as a preliminary approach to estimate the soil engineering property or used in determining the applicability of backfill materials. A significant component of the test is hydrometer analysis which is used to get distribution for the soil particle with size less than 0. 075mm. However,hydrometer test result is usually different even for the same sample by different operators or laboratories. The hydrometer is the most direct approach to obtain the percentage of silt and clay particles although its result is very sensitive to the temperature or its accuracy depends on various factors. This paper is to investage the background of the errors from the stand point of testing and to summarize the misunderstandings of temperature correction method in the current code. A KONGBAI approach is finally recommended in eliminating or reducing the hydrometer analysis errors. This method can be used as a reference in engineering and can be testified by future lab testing.

Analysis of Influence of Foundation Pit Excavation on Adjacent Existing Subway Structure

Yu Xiaolin, Shi Chenghua

2010, 24(4): 202-206. doi: 10.3969/j.issn.1007-2993.2010.04.010

[Abstract](21) [PDF 777KB](6)

Abstract:
In the process of continuous construction and development of urban underground space, more and more foundation pits excavations adjacent subway structures are bringing through. By collecting examples in Guangzhou and in urban, changes of the displacement field after excavation were analyzed and influences of the adjacent constructions of foundation pits on the existing subway structures were summed up. Moreover, Nongmao park project in Guangzhou was selected for numerical simulation using 3D continuous FEM(the finite element method). By comparing and analyzing the results calculated with the measured data, some conclusions which can play reference roles to similar projects in future have been drawn.

Axial Load Testing of Super Length PHC Pipe Piles

Zhou Wanging, Li Xianwu

2010, 24(4): 207-210. doi: 10.3969/j.issn.1007-2993.2010.04.011

[Abstract](49) [PDF 709KB](9)

Abstract:
The bearing capacity behavior and load transfer mechanism are discussed through static and high strain dynamic pile load testing. Results show that the total bearing capacity of test piles by high strain dynamic testing is approximately equal to that by static testing. The lateral friction resistance by dynamic testing is consistent with that by static testing at the depth of 0-30m,but is much larger than that by static testing when the length of the pile exceeds 30 m.

Contrastive Analysis of Ecological Protection Technologies in Rock Slope

Sun Chao

2010, 24(4): 211-213,217. doi: 10.3969/j.issn.1007-2993.2010.04.012

[Abstract](51) [PDF 911KB](18)

Abstract:
Firstly,this paper analyzes the characteristic of rock slope and introduces the conception of ecological protection of rock slope, then synthetically summarizes the ecological protection methods of rock slope, in which four popular methods involved. Finally it pointes out the prospect of the ecological protection technologies in rock slope engineering and the key issues that need to be resolved.

Study on Disposal and Comprehensive Utilization of Construction Disintegraiting Slag in Building Demolition Areas

Chen Guodong, Liang Yonghui, Xu Xiankun

2010, 24(4): 214-217. doi: 10.3969/j.issn.1007-2993.2010.04.013

[Abstract](29) [PDF 630KB](6)

Abstract:
Although construction disintegrating slag which is the mixture of various building waste will damage the environment, it is a highly cycling resource. Construction disintegrating slag will turn waste into building materials by a suitable treatment. This paper describes the composition of construction disintegrating slag and analyzes the its physical and chemical characteristics, and then points out that construction disitegrating slag has the feasibility of reutilization. This paper also introduces the domestic and foreign status, approaches and trends of making use of construction disintegraitng slag, indicates the problems of dealing with construction disintegrating slag in China and last sums up several main disposal ways which !arovides a useful reference to disposal and comprehensive utilization of construction disintegrating slag in building demolition areas.

2010 Vol. 24, No. 4