岩土工程技术

Negative Skin Friction of pile in Self-weight Collapse Loess Site

Ma Kanyan, Zhang Jiwen, Wang Donghong

2009, 23(4): 163-166,177. doi: 10.3969/j.issn.1007-2993.2009.04.001

[Abstract](84) [PDF 345KB](11)

Abstract:
On the basis of vertical static loading test and stress test of bored piles shaft,which built in some places in Guanzhong district along Zhengzhou-Xi'an Railyway Passenger Transportation special Line, under prewetting and afterwetting in self-weight collapse loess, the paper discusses the generating and developing procedure of negative skin friction of pile, and changing procedure of neutral point position, and the action law of lateral friction resistance. The theoretical study and engineering application on negative skin friction of pile in self-weight collapse loess can be quite reference value.

A New Bearing Capacity Calculation Model and Validation of Circular Shallow Foundation

Ren Zhishan, Zhang Huile, Li Congyun

2009, 23(4): 167-171. doi: 10.3969/j.issn.1007-2993.2009.04.002

[Abstract](44) [PDF 341KB](6)

Abstract:
This article assumes that the overall foundation shear damage happened, the sliding surtace damage is given, the greatest possible expansion extent of the soil plasticity balance area with the variety of foundation embedment is considered, and both sides of the foundation soil shear strength are taken into account. Circular shallow foundation bearing capacity is theoretically derived with Limit equilibrium method. Using practical engineering examples and numerical simulation with finite element program (ADINA), the correctness of shallow foundation damage model and theoretical derivation are further validated.

Several Deformation Forecasting Methods for Metro Construction Based on Monitoring Data

Su Yong, Gao Zhengguo, Liao Yiqi

2009, 23(4): 172-177. doi: 10.3969/j.issn.1007-2993.2009.04.003

[Abstract](39) [PDF 389KB](8)

Abstract:
Surface subsidence caused by metro construction can endanger the safety of the surrounding buildings and underground pipelines. How to forecast and control the deformation has becoming an urgent problem in engineering area. The paper has discussed three forecasting ways: Regression analysis method, Exponential smoothing method and Gray theory analysis method, forecasted the ground subsidence caused by shield, mining and foundation construction of Guangzhou metro and compared the forecasting results with the construction measured data. Also the paper has discussed the three ways' suitable for using of construction methods, the range of geological conditions and the problems that should be mind in use based on the analysis results.

The Study on the Pore Water Pressure and Deformation Rule in the Procedure of Mucky Soil's Consolidation

Zhang Xianwei, Lan Xiaolong, Tian Hongqin

2009, 23(4): 178-182. doi: 10.3969/j.issn.1007-2993.2009.04.004

[Abstract](50) [PDF 337KB](9)

Abstract:
In-depth comprehending of the pore water pressure and the deformation in the procedure of mucky soil's consolidation has a significant meaning to study the theory of soil's drainage and consolidation. Though the text of the mucky soil in Huangshi Area, by using the graded loading and once loading into same directional stress consolidation and unidirectional consolidation, to analysis the pore water pressure and the transformative rule during the whole process. The result indicates that two loading methods bring to different rules. Meanwhile the consolidation process will slow gradually when the pressure is lower to the threshold. The pressure will not as distinctive as the initial stage, even when the load is great. The mucky soil's consolidation in drainage has phases, it is caused by the change of the drainage speed about the free water and the leaked water. The main consolidation speed of the mucky soil is around 5minutes to 100minutes. If the consolidation pressure is close to the initial pressure, the consolidation coefficient is at the min. but the secondary consolidation coefficient is the max.

Uneven Subgrade Foundation Soils Influence Analysis to Red Building of Peking University

Yang Guoxing, He Manchao, Wang Shuren

2009, 23(4): 183-186. doi: 10.3969/j.issn.1007-2993.2009.04.005

[Abstract](45) [PDF 393KB](7)

Abstract:
The subgrade foundation soils is uneven according to the geological investigation of Red Building of Peking University. The characteristic of macroscopical deformation is relative with the property, thickness, distribution, etc of the subgrade foundation soils, through FLAC^2D which is a two-dimensional finite-difference program. The result of analysis have a important significance when maintaining and repairing the Red Building of Peking University.

The Calculation of Maximum Saturated Depth in Landfill with Continuous-slope Configuration Drainage System

Zhang Jinli, Wang Tiejun

2009, 23(4): 187-192. doi: 10.3969/j.issn.1007-2993.2009.04.006

[Abstract](38) [PDF 380KB](5)

Abstract:
Maximum saturated depth is an important parameter in designing of landfill leachate dramage systems. Dased on the groundwater flow continuity principles, Dupuit assumptions and extend Dupuit assumptions, phreatic surface governing equations were established over the landfill with slope liner in continuous-slope configuration drainage system, respectively. These equations were solved by numerical calculation. Though computation and analysis of change parameters, the results indicate that Dupuit assumptions can be used to calculate the maximum saturation depth as the slope of landfill liner is less than 10%. When geonet is employed in continuous-slope configuration drainage system, transmissivity of geonet and slope of landfill liner are important influence factors for maximum saturation depth, hydraulic conductivity of protect layer and impingement rates for efficiency of drainage system can't be ignored. At the same time, compared the efficiency of continuous-slope with saw-tooth configuration's in level landfill liner, the results show the former is better than the latter.

Analysis and Discussion on High Pressure Spiral Jet Grouting Test Piles for a Certain Anti-seepage Curtain

Du Changchun, Zhang Ning

2009, 23(4): 193-196. doi: 10.3969/j.issn.1007-2993.2009.04.007

[Abstract](46) [PDF 366KB](7)

Abstract:
Based on the hydrogeology and engineering geological conditions of a certain tandfill in Wenzhou, in the groundwater seepage sand layer, the high pressure spiral jet grouting test piles formed with single pipe method and triple pipes method have carried on the comparative test and analysis. The formed pile-effect and the influence factors of the high pressure spiral jet grouting have carried on the discussion. They can provide important reference for the similar engineering design and construction.

Simulate of the Thrust-sharing in Designed Multi-row Anti-slide Piles

Li Yunhua, Fu Xiaoqian, Wang Xun

2009, 23(4): 197-200,209. doi: 10.3969/j.issn.1007-2993.2009.04.008

[Abstract](69) [PDF 431KB](7)

Abstract:
In the mountain railway construction process, large-scale landslides often used the engineering measures of multirow anti-slide pile reinforcement to reinforcement. The current conventional method of calculation can not calculate the value of the thrust accurately as well as the sharing ratio by the anti-slide pile in each row. In this paper, using large-scale numerical ANSYS finite element software to study Liu Zhan Cao Jia Shan landslide. Using the numerical calculation to get the value of the thrust, and calculate the thrust ratio, this method provides more scientific and rational basis, also avoid those limitations of the former method, and provides a proven solution.

Prevention Technical on Frost Damage of the Plain Reservoir Earth Dam Slope Protection in the Cold Region

Nei Wenjie, Yuan Anli

2009, 23(4): 201-205. doi: 10.3969/j.issn.1007-2993.2009.04.009

[Abstract](49) [PDF 385KB](5)

Abstract:
This paper briefly provides the main content of the prevention technics on frost damage of the plain reservoir earth dam slope protection in cold region which is based on the studies of the frozen soil mechanics and the ice engineering in the recent years. They maybe the references for the engineers because the contents widely include frost damage laws of the plain reservoir earth dams, frost damage prevention methods of the slope protection, prevention methods of the frozen ice, the design parameters determination of resisting the frost heaving and the stabilization calculations of resisting the ice thrust etc.

DFP Method of Inverse Analysis Based on Relative Displacement and Its Engineering Application

Jia Chao, Guo Zhichuan

2009, 23(4): 206-209. doi: 10.3969/j.issn.1007-2993.2009.04.010

[Abstract](17) [PDF 292KB](4)

Abstract:
Some parameters of the rock mass, such as elastic modulus, strength parameters, etc.,are very important to underground tunnel design and construction. Lots of cost are needed if situ-test is done. In this situation, application of displacement inverse analysis theory is very important for real engineering. But unfortunately most uncertain factors cause unavoidable random result for field monitoring, sometimes cause mistake. Factors obtained by inverse analysis on absolute displacement value of situ-test may be error. Such error can be avoided by relative displacement inverse analysis method. In the paper stochastic inverse analysis based on relative displacement method is used in a underground tunnel to calculate elastic modulus factor, and obtained a quite good result.

Buoyancy Discussion and Design Application of Underground Building

Guo Yuelong, Zhang Qinxi

2009, 23(4): 210-213,217. doi: 10.3969/j.issn.1007-2993.2009.04.011

[Abstract](32) [PDF 354KB](8)

Abstract:
This article briefly introduces some new quite convincing research results about buoyancy aspect of underground structure, unifies these research results and the actual load test results of part caking pre-stressed anti-pile pulling, the resistance pile pulling has carried on the optimization design, reduced the investment of anti-floats.

Application of Post Grouting Technology in Foundation Pile of New CCTV Main Building

Lu Qingjian, Chen Changfu, Ma Yongqi

2009, 23(4): 214-217. doi: 10.3969/j.issn.1007-2993.2009.04.012

[Abstract](21) [PDF 273KB](5)

Abstract:
Because of the advantages of simple construction, large bearing capacity increases,the post grouting technology has been widely used. With the practical project, the paper introduces the field test study of grouting in different length of bored pile, analyzes the characteristics of bearing deformation. The application of post grouting technology is successful in practical project.

2009 Vol. 23, No. 4