岩土工程技术

Analysis on Settlement of Pile-group With Soft Underlying Stratum

Zhang Qianqing, Zhang Zhongmiao

2009, 23(5): 217-222. doi: 10.3969/j.issn.1007-2993.2009.05.001

[Abstract](42) [PDF 386KB](6)

Abstract:
The settlement of pile-group consists of the compression deformation of pile shaft and the settlement of pile tip. In this paper, the compressive deformation of single pile shaft is calculated by adopting hypothesis of linear-elasticity, and the compressive deformation of pile-group shaft is approximate to the compressive deformation of single pile shaft. Moreover, the additional stress of pile tip is obtained by multiplying the average stress under pile cap or raft and the coefficient of transfer load. All these researches deduce the means of calculation of pile-group settlement with soft underlying straturr, In the end, the present method is compared with another method and practical project test results.

The Stability Analysis of Slope Based on FEM strength reduction

Li Pengfei, Chen Wenwu

2009, 23(5): 223-226. doi: 10.3969/j.issn.1007-2993.2009.05.002

[Abstract](37) [PDF 299KB](7)

Abstract:
In this paper, apply "FEM strength reduction" to carry out slope stability analysis, at the same time, apply "Bishop's simplified method" to compare the result. Follow the reduction factor increases, the maximum horizontal displacement that at the top of slope was increased slowly in the initial stage, but when the reduction factor close to the safety factor, the maximum horizontal displacement was reduced quickly. And, follow the reduction factor increases, the plastic zones from scratch, until through. For comparing, I find the damage surface that calculated by the two ways,are basically consistent, but the safety factors are conservative by the "Bishop's simplified method".

Application of Neural Network to Compaction Parameters in Pavement Base

Hua Mingjie, Wang Baotian, Wang Yinghe

2009, 23(5): 227-231. doi: 10.3969/j.issn.1007-2993.2009.05.003

[Abstract](41) [PDF 345KB](5)

Abstract:
The semi-rigid material of lime stabilized industry wastes is commonly used in pavement base of high-grade highway, which contains certain aggregate or none aggregate according to the requirements of standard and design. Generally, the indoor heavy compaction test is not only labor-consuming, but also unable to achieve the precise compaction parameters of the semi-rigid mixture when the aggregate is over 50%. Based on the known compaction parameters of the binder without aggregate and combined with artificial neural network theory, the simulating network model of this type of semi-rigid material's compaction parameters was created by BP network in Matlab. Through large amounts of training, adiustment of training function and transfer function and normalization of initial input data, eventually the 6→15→2 network was established. The results simulated by the network model are correct and stable, which show certain practical application values.

Analysis of the Tunnel Excavation Under Considering the Seepage Field

Zhao Erxiang, Gao Jiangtao

2009, 23(5): 232-236. doi: 10.3969/j.issn.1007-2993.2009.05.004

[Abstract](60) [PDF 298KB](5)

Abstract:
The initial geostress and seepage field are destroyed because of tunnel excavation. Take circular tunnel for example,the distribution of stress field, pore water pressure and displacement field after tunnel excavation will be obtained with Finite-difference procedures considering seepage force. Meanwhile, the difference of displacement field is contrasted between whether or not take into account seepage effect and also the different distribution of displacement field under diverse water line. Eventually, the relative suggestion of waterproof and drainage, design and construction on tunnel is provided.

A Discussion on the Application of TSP in Tunnel of Shizhucao for Tunnel Geological Prediction

Liu Yongsheng

2009, 23(5): 237-241. doi: 10.3969/j.issn.1007-2993.2009.05.005

[Abstract](36) [PDF 480KB](4)

Abstract:
The authors introduced the common tunnel disaster and the key elements of tunnel geological predic tion. Through cases, the author disscussed the TSP' application effects and some key problems.

The Analysis of Stability of Surrounding Rock Inintersection Tunnel in Jinping Ⅱ Hydropower Station

Li Xusheng, Gao Bo, Shen Yusheng

2009, 23(5): 242-245,250. doi: 10.3969/j.issn.1007-2993.2009.05.006

[Abstract](46) [PDF 417KB](4)

Abstract:
The complex geological condition including great depth will bring about many engineering problems in Jinping Ⅱ Hydropower Station, so excavation of an main tunnel which is intersected with a tunnel can weaken the quality of surrounding rock(expecially in intersectoin). Considering deeply-rock, we analyzed the mechanical of stress release and redistribution in the surrounding rock using 3D elastic plasticity finite element numerical and model experiment, This study offers references for design of the monitoring system, construction scheme optimization, and safe control of deeply buried tunnels.

Study on Factors Influencing the Displacement Characteristic of Underground House in Stratified Rock

Zhang Zhanrong

2009, 23(5): 246-250. doi: 10.3969/j.issn.1007-2993.2009.05.007

[Abstract](76) [PDF 397KB](6)

Abstract:
Underground houses are mostly used in the construction of hydropower station, and the deformation characteristic of the surrounding rock is a key problem in the design and construction process. By using the FEM soft and the orthogonal experiment, the influence of multi-factor changing was taken into account, to study the influencing degree of the deformation characteristic of the surrounding rock by each factor, and the order of the influencing degree was listed. From the results we can see, the biggest influencing factor of vault displacement were the thickness of the rock stratum and the depth of the underground house, and the centre of the left side wall were the height and the depth of the underground house, the center of the right side wall was the depth of the underground house. The position of the biggest deformation was mostly near the centre of the left side wall. The biggest influencing factors of biggest displacement were the thickness of the rock stratum, the depth and the height of the underground house. At last, the influencing trend curves of the factor for the displacement of specific position were drawn.

Monitor and Analysis on Excavation With Cement-soil Anchor Pile

Chen Weigang, Liu Quanlin

2009, 23(5): 251-254. doi: 10.3969/j.issn.1007-2993.2009.05.008

[Abstract](38) [PDF 197KB](9)

Abstract:
Cement-soil anchorage is an initiative technology to reinforce soil excavation and getting more Application in shanghai and jiangsu. By an example which is changshu-wanhao light textile city, analysis the monitoring data about the envelope construction and surrounding environment during Construction process, Confirm this support structure is safe, reliable and economical.

Study on the Method for Unsaturated Soil Permeability Test Based on GDS System

Chen Changfu, Li Shuwei

2009, 23(5): 255-257. doi: 10.3969/j.issn.1007-2993.2009.05.009

[Abstract](50) [PDF 196KB](5)

Abstract:
The unsaturated soil permeability test is an important way to study permeability characteristics of unsaturated soil. Due to the difficulty of measuring permeability coefficient directly, most research work based mainly on theory. This paper study on the method for unsaturated soil permeability test. The results show that the unsaturated soil permeability test based on GDS system is efficient for measuring permeability coefficient which provide a good research approach.

3D Simulation Study on Excavation Process of Big-span Road Tunnel

Zhao Chunyan, Hao Zhe

2009, 23(5): 258-262. doi: 10.3969/j.issn.1007-2993.2009.05.010

[Abstract](41) [PDF 493KB](5)

Abstract:
By FLAC-3D, the whole process of excavation of big-span highway tunnel was simulated. Stress, deformation, plastic state of surrounding rocks at various phases were given. Stability of tunnel was evaluated. By the 3D simulation of excavation process, distribution of stresses and support can be known, influence on stability of surrounding rock in construction can be analyzed, and it can provide important references.

Technology of Cut off Wall Construction by Vibrating Grooving

Duan Yufeng, Zhan Bo, Ceng Pengjiu

2009, 23(5): 263-267,271. doi: 10.3969/j.issn.1007-2993.2009.05.011

[Abstract](29) [PDF 419KB](4)

Abstract:
There were lots of new technologies on cut off wall construction in which vibrating grooving was one. Wall formation principal, processes and equipments were introduced in this paper. Vibrating grooving is a technology of simple and practical, high efficiency and quality stability, which has been applied to sand and soil layer construction and has wide application prospect.

Engineering Example of Ground Treatment of Subgrade of Disease Area

Jiang Zhian

2009, 23(5): 268-271. doi: 10.3969/j.issn.1007-2993.2009.05.012

[Abstract](23) [PDF 275KB](4)

Abstract:
To prevent the settlement of subgrade of Qingdao-Jinan only-passenger-transported railway, a scheme was suggested that the Down-hole drill was used to penetrate the filled soil, and high pressure jet grouting technique was adopted for reinforcing and strengthening the foundation. In the course of construction, the procedure of high pressure jet grating was optimized, this method does not only ensure the safety of the existing railway operation, but also give a guarantee to railway quality under construction, then the engineering problem was solved effectively. After the optimum scheme was testified, it would have the value to be analyzed further and extended.

2009 Vol. 23, No. 5