2008 Vol. 22, No. 6

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Display Method:
Probe Into Landslide Stability Evaluation
Zhang Sumin, Zhang Kuangcheng
2008, 22(6): 271-276.
[Abstract](135) [PDF 334KB](11)
Abstract:
There are three issues discussed. First, the landslide stability evaluation judgment indices of the segmented sliding surface are analyzed. In addition to the index of residual downslide force Pn, the evaluation analysis by the landslide stability indices of the KT type and R/K type are introduced. Second, based on the comparative analysis of the calculating methods of the stability indices, such as segmentation equilibrium method, summation equilibrium method, horizontal projection method, and so on, the practical significances, advantages and disadvantages, scope of the application of the methods are proposed. Third, the different concepts of K value in the landslide stability evaluation, back calculation of shear strength parameters and the calculation of landslide thrust are investigated.
Critical Slip Field Method For Slopes in Terms of Energy
Li Liang, Chu Xuesong
2008, 22(6): 277-280.
[Abstract](31) [PDF 577KB](5)
Abstract:
The method of critical slip field for slopes is newly developed by Prof. Zhu Dayong. The unbalanced work is defined as the difference of virtual work of loadings to inner energy dissipation and the new method of critical slip field in terms of energy is presented. This new method includes two calculating steps, i.e. the determination of slip surface yielding the maximum unbalanced work with regard to given factor of safety and the determination of minimum factor of safety, under which the maximum unbalanced work is zero. Two typical soil slopes are analyzed by using this new method and the comparison of results proved its validity. This new method is characterized by simplicity of calculation and the avoidance of assumption on inter-slice forces.
Earth Pressure in Deep Soils and Influences to Thickness of Frozen Wall
Zhao Xiaodong, Zhou Guoqing, Xu Zhiwei
2008, 22(6): 281-285.
[Abstract](40) [PDF 718KB](5)
Abstract:
Based on summing up earth pressure calculating formulas in the deep and thick soils,the properties of earth pressure are presented according to the construction process of freezing engineering. In addition,the relations between extrusion (relaxation) displacement and extrusion (relaxation) stress Ps are obtained from horizontal loading (unloading) tests of remodeled deep soils experienced high pressure Ko consolidation and the calculating errors of earth pressure as well as thickness of frozen wall caused by neglecting Ps, are investigated too. The results indicate that earth pressure in deep and thick soils should be selected in accordance with the construction process of freezing engineering in order to avoid project accident.
Nonlinear Dynamics Model of Rock Evolution and Stability Analysis
Sun Yinglin, Xu Chuanhua, Han Shaoying
2008, 22(6): 286-288.
[Abstract](37) [PDF 192KB](6)
Abstract:
On the basis of displacement-time series, a nonlinear dynamics model is set up with support vector machine. The longest forecasting time is provided according to Lyapunov exponents and a standard cusp catastrophe model can be obtained through varibte substitution and function fitting. The results shows that this model can make satisfactory prediction results.
Formation Reasons for Sand Density and Study of Evaluation Methods
Kong Xiangguo
2008, 22(6): 289-291,311.
[Abstract](40) [PDF 375KB](11)
Abstract:
The density of the sand is important factors for their engineering properties, the evaluation methods of sand density is more, but the results may have differences, usually means, this is testing error that is caused by different testing method. In fact, the causes of the sand formation and buried conditions, groundwater is also the important factors. The distribution of effective stress in the soil will be changed by the pressure of the confined water, and the anomaly of sand density may he formed. Project should focus on the analysis of the formation reasons for sand density, according to theoretical knowledge, to identify applicable conditions of various evaluation methods and their advantages and shortcoming.
Method of Achievements in Quality Control of Network RTK
Zhu Zhaorong, Wang Shengguo
2008, 22(6): 292-294.
[Abstract](34) [PDF 303KB](5)
Abstract:
Along with the development of reference station technology oi GF5 and Uomputer tecnnology anu network technology, the Network RTK is developed and applicated quickly. It explains the construction of continuously operating GPS reference station and the principle of Network RTK operation, also explains the importance of quality control, affect the Network RTK operation factor, methods of quality control and so on. Through appropriate equipment of Network RTK and opera tional mode. using all methods of quality control, can obtain stable, reliable,real-time and precise result.
Distribution Rule of Blast Loads on Large-span Compound Structure
Ma Linjian, Zhou Zhenzhong, Sun Bo
2008, 22(6): 295-298.
[Abstract](36) [PDF 734KB](5)
Abstract:
In order to analyze the distribution of the load on the large-span compound structure in rock and soil under explosion, by applying LS-DYNA program to simulate different operation conditions, the variety and the distribution of the load is gotten on some typical span arch shell structures. The result shows that the load on the arch shell structures attenuates from vault to two sides as time goes by; the load's acceptance range minishes as the structure span increases until it reaches 50m, the distribution of the load offsets as deflection angle of the explosion source to the structures changes with the same distribution form.
Slip Mechanism and Stability Analysis of Rock Landslide Based on Reversed Fault
Shao Jiang, Xu Jiliang
2008, 22(6): 299-303.
[Abstract](37) [PDF 778KB](5)
Abstract:
Based on a rock landslide on a express way,it is described that the conception and characteristic of the rock landslide based on reversed fault,and the slip mechanism and the slip process is summarized, the stability of the landslide on different condition is analyzed. It is useful for the survey. design and construction of the similar work.
Calculation of Deformation Modulus of Two Layers Composite Ground Based on Loading Test
Shi Shaomin, Liu Junlin
2008, 22(6): 304-307,319.
[Abstract](46) [PDF 397KB](10)
Abstract:
Two dwelling buildings with 18 stores are proposed on a ground consisting of,soft marine clay. The foundation is treated with vibroflotation. Based on the comparison of the load tests and the settlement curves, it is founded that the modulus on initial linear part of the curve of load tests does not truly express the compression of the composite ground for the raft-foundation and that the settlement is related with later linear part of the curve of load tests This article is about the calculation method of the deformation modulus of two layers composite ground within the plate influence from the data of load-test. It is close that the calculation settlement with the modulus compared with the calculation settlement with the measured settlement of the two buildings. The two layers modulus from load-test is avoid of the defect of the using method which only one layer modulus of deformation is gained.
Combined Application of Excel and AutoCAD to Draw Soil Test Curve
Luo Hui, Liu Zunping
2008, 22(6): 308-311.
[Abstract](60) [PDF 297KB](7)
Abstract:
In general, soil test datum arrangement process of highway engineering is difficult to use a single drawing tool making the double logarithmic graph reach satisfactory results. Excel has excellent data processing and statistical functions, but its graphics effect is not regular and beautiful; Compared with Excel, AutoCAD has fast and accurate mapping and editing features, but its data processing capability is poor. Making full use of their respective advantages handle soil test in the double logarithmic graph is a very convenient and practical method.
Design and Construction of Retaining Structures for Deep Foundation Pit to Protect Limited Width Soil
Zhang Huaiwen, Ji Xiaopeng, Che Dong
2008, 22(6): 312-315,323.
[Abstract](33) [PDF 840KB](8)
Abstract:
On the basis of the assumptions of Rankine's earth pressure theory and the Limit Equilibrium theory, the limited width soil is translated into the semi-space soil, so that their horizontal earth pressures are fitted to each other. Then, as an example, a deep foundation pit to protect the limited width soil is designed and constructed according to the software of pit-retaining. In addition, large-angle anchors and double-row piles at certain place are applied in this design. As a result, the monitored horizontal displacements are all within the standard limit of design, therefore it can be a reference for similar projects.
Landslide Characteristics and Countermeasure of West-East Gas Transportation Pipeline Project
Su Peidong, Yao Anlin, Jiang Hongye
2008, 22(6): 316-319.
[Abstract](24) [PDF 335KB](8)
Abstract:
The gas pipeline from west to east in China exceeds 4000 km. There are 155 landslides along the pipeline. But only 17 landslides are unstable. Most of the unstable landslides are located in Ningxia, Shaanxi and Shanxi which are shallow loess landslide and deposit landslide. The formation mechanism of the unstable landslides include the landform and physiognomy, stratum lithology, river erosion and man-made factors. The danger to the pipeline and its attached facilities are researched. The countermeasures of prevention and treatment are proposed, such as anti-slide retaining wall, slope leveling and waterproofing.
Several Geotechnical Engineering Problems During the Construction of Power Plant in the Coast of Indian Ocean
Li Zhongming, Li Chaoyang, Liu Hongwei
2008, 22(6): 320-323.
[Abstract](37) [PDF 936KB](6)
Abstract:
Based on the geography and geological environment of the coast and the characteristic of the coal power plant, several major geotechnical problems, the causes, characteristics, constraints and impact of the construction of the project are analyzed, and then the countermeasures and suggestions are proposed to solve these problems.

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