岩土工程技术

Numerical Simulation of “Wedge” at Left Abutment of Jinping First Stage Hydropower Station

Lin Xingchao, Wang Yujie, Xu Nengxiong

2009, 23(2): 55-59.

[Abstract](51) [PDF 720KB](6)

Abstract:
There is a complex geological condition in the left bank of Jinping First Stage Hydropower Station. The wedge's stabilizing is one of the most important problems in the project which is composed of several weak layers. Support methods such as pro-stressed anchors system and shear key were adopted to ensure wedge safety. In order to research the two support methods and construction processes' influence in slope stability, the slope continue excavating with the two support methods in deferent construction processes have been used for numerical simulation. After comparison of plastic zone and variation of displacement, it is find that pro-stressed anchors system have an effect on limiting the development of plastic zone, refilling shear keys have en effect on control the displacement of the fault f42-9 which is the bottom slip surface of the wedge. It is very important for the left bank slope stability that completed the two support methods in time. It is feasibly that to decide slope stabilizing by curves of relative displacement between two sides of typical wake layer.

Application of Three Dimension Laser Scanning Technology in Shuanglong Cave Surveying

Zhang Lei, Zhang Jingwen, Hu Zhenhai

2009, 23(2): 60-63.

[Abstract](64) [PDF 574KB](4)

Abstract:
The application of three dimension laser scanning technology in Shuanglong Cave surveying is introduced. The study not only improves the accuracy and efficiency of cave surveying, but also provide data source for modeling three-dimensional visualization of interior topography of cave and the shape of geological body, for constructing of the virtual geographical environment of cave and the construction of geography information system of cave. It can provide intuitive and precision basic data for the data base of cave, the development of landscape tourism of cave, the protection of environment and landscape of cave and the cave archeology.

Mechanism and Prevention Measurement of Geological Hazards Occurred on Old Accumulation of Debris Flow

Li Yushu, Li Tianbin

2009, 23(2): 64-67,71.

[Abstract](60) [PDF 385KB](8)

Abstract:
The hazard of old accumulation of debris flow that occurred under the factors induced by engineering activities of human beings still hasn't aroused people's attention. The Bietuo old accumulation of debris flow where the Bietuo segment of west approach road of Erlang Tunnel on Sichuan-Tibet Highway is selected as a case to introduce it's evolution and it's fabric character, then analyze the mechanism of the geological hazards along the highway, and finally, generalize the hazard effect and the corresponding prevention and cure measure when taking activities of engineering on old accumulation of debris flow.

Foundation Design Optimization to Frame Structure With Spread Basement

Du Xinghua, Cao Jian, Chen Rongbin

2009, 23(2): 68-71.

[Abstract](37) [PDF 297KB](4)

Abstract:
Floatage force often occurs and produce strong effect on building in coastal area or other high ground-water level area. Therefore, foundation anti-floatage design becomes a key problem of construction in these areas. In general, anti-lift pile foundation is taken to counteract the adverse effect of ground water floatage to building in sub-ground engineering. But, anti-lift pile foundation is not the only measure and it has been proved times and again, so more economical and reasonable foundation is called in relation to certain engineering condition in design works. Based on certain engineering case, security and economical rationality of its foundation design is analyzed, and an optimized foundation scheme is put forward. The foundation design optimization could produced some inspiration to other foundation design.

Optimum Design for Cross-section of Gravity Retaining Wall Based on lstOpt Software

Wang Lei, Dong Guoliang

2009, 23(2): 72-74,78.

[Abstract](41) [PDF 262KB](4)

Abstract:
In order to solve the complicated calculating indexes and difficulty to draw the best results of the retaining walls design. The smallest cross-section objective function of the gravity retaining wall is established which can meet the stability and the requirements of the bearing capacity of foundation, get the non-linear mathematical optimization model and a domes-tic mathematical optimization software lstOpt is used to solve. This method avoids the cumbersome process of the trial calculation and a reasonable cross-section of economic size could get, and has been successfully used in Zhong Wu gas line along the protection of hydraulic engineering.

Experimental Study on Seepage Control by Means of Suspended Cut-off Wall With Landside Seepage Berm

Li Xiangfeng, Wang Baotian, An Yanyong

2009, 23(2): 75-78.

[Abstract](65) [PDF 284KB](4)

Abstract:
The model test on effect of suspended cut-off wall with landside seepage berm on controlling the piping in sandy foundation of levee was carried out in a flume. The experimental results for different suspension depths an different berm width were obtained. It is found that the cut-off wall and landside seepage berm can effectively block the seepage deformation and control the development of piping when the seepage happened. There is a conclusion that landside seepage berm is not less effective than suspended cut-off wall in big degree of penetration, but is a reliable anti-seepage measure from economy aspect.

Effect Testing of Dynamic Compaction on Berth Field of a Dock

Gan Qiling

2009, 23(2): 79-81,86.

[Abstract](48) [PDF 222KB](9)

Abstract:
Dynamic compaction method is adopted in ground treatment of the design for engineering containers of a certain dock and multipurpose berth field. For the purpose of testing technological parameters of construction and inspecting the effect of dynamic compaction, this design adopts some inspecting methods, such as soil tests, single-bridged CPT, observation of water level and pore water pressure, shallow plate loading tests, modulus of resilience, density of compaction, CBR tests and so on. All these testing methods serve as clear guides to the large-scale construction on site.

Influence of Weak Intercalation Within Red Beds to Pile Foundation of Bridge

Liu Lianggui, Peng Gongxun, Li Chenghai

2009, 23(2): 82-86.

[Abstract](44) [PDF 355KB](4)

Abstract:
During designing and quantity-controlling of pile foundation of bridges, it's always inclined to handling briefly and dogmaticly around weak intercalation. Accordingly, the influence of weak intercalation within red beds to pile foundation of bridge is analyzed. It's concluded that the problem can be processed in different way under different condition.

Study on Fitting of Helicoid

Chen Jiwei

2009, 23(2): 87-89,94.

[Abstract](34) [PDF 272KB](4)

Abstract:
A new method of helicoid fitting is put forward, that construct error equations using the algebra relation between parametric function and Cartesian system of coordinates. Each parameter of the helicod is extracted by numeric solution of the non-linear equation named multi-dimension numerical value root-seeking. The results of several computational experiments show this method is efficient and accurate. This method can be developed to other surface fitting.

Chemical Characteristics and Origin of Geothermal Water in Shandong Shenxian Hollow(Liaocheng Segment)

Wang Kuifeng

2009, 23(2): 90-94.

[Abstract](31) [PDF 362KB](4)

Abstract:
Studies of the origin and evolution mechanism of groundwater in a type area not only have great slgnificance for guiding the rational utilization and development of geothermal water resources but also provide important information for future geothermal resource exploration and evaluation. The formation and evolution of geothermal water in the Shenxian Hollow (Liaocheng segment) is studied based on an analysis of the chemical composition, isotopes and hydrogeological characteristics of geothermal water in the area. The study shows that the formation of the geothermal water is controlled by deep faults and basement structure in the area, the hydrochemical components consist predominantly of more soluble salts, and gas components are mainly marked by a mixture of components originating from the atmosphere, all these reflect the various hydrochemical processes in long-term run-off and deep circulation of groundwater.

Compensation Design and Test of a Weak Intercalation

Zhang Haidong, Xie Xiaofeng, Liu Tianshu

2009, 23(2): 95-99.

[Abstract](37) [PDF 526KB](6)

Abstract:
According to the complicated geology conditions of the foundation's main bearing stratum which partial contains weak intercalation, treatment methods are usually be used such as replacement method and composite foundation. Combined with practical work, some reinforcement designs are introduced and the applicability of the construction methods are discussed. In the base of the former research results, the new idea of reinforcement design through control settlement is been proposed. In view of the difficult problems that treated foundation is invisible and can not excavation to test directly, the multichannel transient surface wave method is be quoted firstly to test the reinforcement effects and the result is satisfied. It can be a useful reference for similar engineering practice.

Extruding Mechanism Comparative Study of Squeezed Branches and plates Pile and DX Pile

Li Weiwei, Li Congyun

2009, 23(2): 100-105.

[Abstract](44) [PDF 385KB](5)

Abstract:
Squeezed branches and plates pile and DX squeezed pile are new types of pile developed from normal bored pile. Compared with normal bored pile, its ability to afford the load of individual vertically and unit consumption of concrete is apparently higher and its social and economical profit is obvious. First, It conducts a comparative study of two extruding devices (one-way extruding device and two-way extruding device), and concludes that the bearing capacity of branches and plates formed through two-way extruding device is much better than that of branches and plates formed through one-way extruding device. After analyzing the process of plates being formed through two kinds of equipments, a method is provided to draw the outline of two types of dishes respectively, and deduces the formula of dish volume which affords the load.

Numerical Analysis of on Settlement of Cement-soil Mixing pile Composite Foundation

Fu Guihai, Zhou Hui, Jiang Xueliang

2009, 23(2): 106-108.

[Abstract](42) [PDF 208KB](5)

Abstract:
On the basis of real engineering, the FEM is applied to anlyse numerically on settlement of cement-soil mixedpile composite foundation, and the factors including space among two piles, pile length, pile modular, underlying layer modular to effect on settlement of composite foundation are analyzed. The conclusions of settlement of cement-soil mixedpile composite foundation are obtained. The conclusions has guiding significamce for the similar engineerings.

2009 Vol. 23, No. 2