岩土工程技术

Viewpoints on Statistical Inference for Geotechnical Sampling

Li Zhengyi

2008, 22(3): 109-112,122.

[Abstract](32) [PDF 221KB](8)

Abstract:
It is common that geotechnical samples are delimited according to the natural geological origin and period. The necessity of dispersion of geotechnical sampling probability distribution, and the degree of diversity is relative to partitioned range of the base layer are expounded. Based on the analysis result of the applicability of variation coefficient and the generality of sampling, the use of the resemblance index to appraise the degree of the dispersion is advanced, and the number of geotechnical samples must be strictly controued according to the principle of relative capacity. The author suggests, according to the essence of the base layer to infer the risk limit data, should be by another method in a small amount samples condition.

Performance Study on Slope Slip Surface Generation by Spline Function

Li Liang, Wang Qiusheng

2008, 22(3): 113-118.

[Abstract](28) [PDF 480KB](5)

Abstract:
The two-dimensional slip surfaces are usually generated by connecting a series of nodal points, of which the coordinates are optimized to locate the critical slip surface. The more the number of nodal points is, the more the number of optimization variables. Based on several nodal points, the Spline function can be used to generate smooth curve as the slip surface. And it is also applicable to the soil slope containing soft layers without pre-definition of lines between two adjacent nodal points. The factor of safety related to the given slip surface is obtained by unbalanced thrust force method and the harmony search algorithm is adopted to determine the critical slip surface for three soils slopes. The performance study on the generation of Spline Function is performed.

Stability Analysis for Soil-Rock Composite Slope

Zhang Lianhua, Tang Lingxiang, Luo Kang

2008, 22(3): 119-122.

[Abstract](41) [PDF 388KB](8)

Abstract:
For soil-rock commixture, there is no standard model of design calculation in existing criterions. Based on the investigating data, the circular sliding method is adopted to search the most dangerous potential slide surface in the intenseweathered layer and the soil. And the most dangerous potential slide surface is in combination with the structure surface of the mid-weak weathered layer,and the transmission coefficient method can be used to carry out the overall stability analysis.

Sensibility Analysis of Soil Slope Stability on Mechanical and Geometrical Parameter

Liu Lipeng, Yu Hongjie, Chen Qi

2008, 22(3): 123-126.

[Abstract](41) [PDF 189KB](9)

Abstract:
Based on the FLAC2D finite difference software, strength reduction theory has been used to gained the stability factor of the 48 soil slopes under the different conditions. Grey Correlation Analysis Method of the Grey System Theory is employed to analyze the sensitivities of factor influencing slope stability. The matrix of correlation data is set up, the elements of which are then transformed to dimensionless parameters. The grey correlative factors and grey correlative degrees which respect to the influencing factor and the slope stability factor are computed, and the sensible factors influence slope stability are determined. The results show that the cohesion of the soil, the density and the internal friction angle are the most sensitive factors to the slope stability, and the dilatancy angle, slope angle and the slope height are taken second place, which provide a reference to the reasonably and effeetively design of the actual slope works.

Secondary Inner Force Analysis of Column-Anchor Retaining Structure with Concrete Creep

Wang Houyu, Liu Zhijie, Yan Zhixin

2008, 22(3): 127-130.

[Abstract](27) [PDF 361KB](5)

Abstract:
A practical method of secondary inner force analysis is presented for column-anchor retaining structure considering concrete creep based on concrete aging creep theory and equivalent elastic modulus. The results of secondary inner force of a detail retaining structure are also presented and discussed. It is demonstrated that the secondary inner force increases with the increasing of earth pressure or with the increasing of excavation depth under downward construction. The results also show that it is necessary to consider concrete creep for retaining structure near wall toe because the secondary inner force of this section is larger than others.

Model Test Research for Eccentric Prestressed Anchor Rope Anti-slide Pile

Jin Bo, Cheng Fangfang, Chen Ningning

2008, 22(3): 131-135,138.

[Abstract](44) [PDF 1176KB](5)

Abstract:
Eccentric prestressed anchor rope anti-slide pile is also called eccentric pile. It is a new type anti-slide pile structure. It is first advanced and applied for landslide correction of Huang Yah expressway(k224). Based on the result of the large model failure test of eccentric pile in laboratory test, the deformation failure regular, circumstances and design theory of calculation is researched. The research provids reference for the application of eccentric pile.

Analysis of Bearing Capacity of Ram-compacted Piles With the Bearing Base in Chengdu clay

Chen Zhuitian, Zheng Yuhui, Wang Huichang

2008, 22(3): 136-138.

[Abstract](30) [PDF 152KB](7)

Abstract:
The bearing property of ram-compacted piles with the bearing base in Chengdu clay is discussed and the bearing capacity is estimated based on the Specification for Design of Ram-compacted Piles With Bearing Base(JGJ 135-2007)and the loading test result of the first engineering example of ram-compacted piles with the bearing base in Chengdu clay.

Computation Method of the Single Pile Bearing Capcity of Post-grouting Spinning Drill Pile

Liang Jinguo

2008, 22(3): 139-144.

[Abstract](30) [PDF 366KB](8)

Abstract:
Based on the in-site measurement results of the post-grouting spinning drill pile, the engineering properties, load transferring law and side-friction distribution law of pile are analyzed. The development degree of side-friction of the pile, which subjected vertically loads, decays with the buried depth of the pile. The distribution relationship of development degree of side-friction, toe-friction and computation method of the single pile bearing capacity of the post-grouting spinning drill pile are provided. Theory basis for design of post-grouting spinning drill pile are provided.

Modified Priebe Method for Settlement Calculation of Vibroflotation Composite Foundation

Huang Xiaojun, Chen Chen, Bian Lijie

2008, 22(3): 145-147,151.

[Abstract](40) [PDF 224KB](7)

Abstract:
Based on the analysis of the classic Priebe settlement calculation method, assumption of stone column compressibility thuough replacement ratio change is improved. The bulk density differences of the stone column and soil and the relationship of the stress, deformation and depth under load stress are studied, and the corresponding coefficient formula deduced. Finally, the project is verified, the result shows the improvement is reasonable and can be a reference.

Anti-freezing Effectiveness Analysis of Aline Region hydraulic structures in Seasonally Frozen Area

Nei Wenjie, Yuan Anli

2008, 22(3): 148-151.

[Abstract](30) [PDF 656KB](5)

Abstract:
It has gained the obvious effectiveness that applying the EPS heat insulating boards to the foundation of hydraulic structures can resist the frost heave damage of the foundation, the EPS heat insulating foundation is observed for four winters and springs and the temperature field of the foundation is analyzed by in-situ simulating in the field,and the observation data are obtained. The test result validates the feasibility that the EPS heat insulating foundation method can reduce the frost heave from the analysis of temperature field changing laws with different density and different thickness of the EPS heat insulation foundation. It can offer referring gist for consummating the anti-frozen theory and practical experiences.

Design and Construction of a Deep Excavation Slope in Nanjing

Wang Jing, Lu Jun, Tan Yuehu

2008, 22(3): 152-154,159.

[Abstract](56) [PDF 213KB](8)

Abstract:
The circumstance of deep excavation in Nanjing is more complex, which the groundwater is rich and the excavation is more deeper with the depth of 13m. According to the depth of the circumstances of the excavation, The bored piles and soil anchor-bar are adopted. The technical points of construction is analyzed. The support method is feasible by monitoring results.

Physical Components and Microstructure Characteristics of Loess in West of Liaoning

Xing Yudong, Zhu Fusheng, Wang Changming

2008, 22(3): 155-159.

[Abstract](25) [PDF 1604KB](9)

Abstract:
Physical composition and microstructure of loess have an important significance to research further engineering geological characteristics, collapsibility and its mechanism. So the physical components such as particles, chemical composition, mineral component, soluble salines and microstructure of leoss along the line of Fuxin-Chaoyang freeway, are tested and analyzed by means of particle analysis, X radial diffract technique, chemical test and scanning electron microscope(SEM). As a result, some conclusions are drawn as follows:①Silt grain is main part in loess, and content of coarse silt is great. The content of clay grain has a larger range. ② The drossy minerals in loess are mainly comprised of quartz and feldspar. Illite and blending of montmorillonite and illite take a dominating position in clay mineral.③ The content of diffluent saline and hardy-soluble saline in loess are less than other areas in China. And ④ the structure loess is looser in shallow depth, and denser in deeper depth. There are weak-cemented structure with bracket particles and big pores and half-cemented structure with bracket particles and big pores to inlay particles and micro pores in cemented structure in deep depth. shallow depth, and flocculent-cemented structure and clotted-cemented structure in deep depth.

Calculation of Active Earth Pressure For Tilted Fill

Liu Fuchen, Fang Jing, Lin Shile

2008, 22(3): 160-163.

[Abstract](44) [PDF 258KB](9)

Abstract:
In the supporting structural engineering, the calculation of the active earth pressure is not suitable for the theory of the earth pressure when the fill surface is tilted. The problems for The Technical Code For Building Slope Engineering, and recommended a new method are discussed. The calculation shows the advantage of simple and reasonable.

2008 Vol. 22, No. 3