2012 Vol. 26, No. 2

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Development and Creation
Quantitative Evaluating Method of Non-uniform Foundation With Excel VBA
Liu Dahai
2012, 26(2): 55-58. doi: 10.3969/j.issn.1007-2993.2012.02.001
[Abstract](41) [PDF 637KB](6)
Abstract:
The quantitative evaluation of non uniform soil-foundation is large amounts of work to do and the manual calculations are quit complicated. With Excel VBA, pursuant to "Specification for geotechnical investigation of tall buildings(JGJ 72-2004)", its Excel VBA procedure is compiled. The Excel form of measure results can be taken into the project documents directly.
Study of Longitudinal Long-term Stability of Shield Tunnel in Soft Clayed Soil
Yu Long
2012, 26(2): 59-64. doi: 10.3969/j.issn.1007-2993.2012.02.002
[Abstract](41) [PDF 840KB](3)
Abstract:
According to the similitude relations for the centrifuge rmdd test, the consolidation time of centrifugal model is 1/n2 of the prototype, which could simulating the soft soil foundation long——term settlement in a relatively short time. The method was used to study the longitudinal long term settlement and stability of the paralld shield tunnel of the subway line 4 in Shanghai. Form the results, the longitudinal settlement of the intact, repaired and connected tunnel could be predicted. The conclusion was that the differential settlement of connected tunnel is the largest, and the connection with the repair section of the tunnel should be rigid, which should be used to improve the ability adapting to the defon'nation the tunnel.
Preliminary Study of Equivalent Depth Calculation in Pit Retaining
Zhu Yanbing, Zhou Xiaohua, Liao Shaoming
2012, 26(2): 65-69. doi: 10.3969/j.issn.1007-2993.2012.02.003
[Abstract](56) [PDF 784KB](6)
Abstract:
Problem of "pit in pit" (PIP)is a universal problem which hasn't been researched deeply. It is the realistic meaning for the PIP's equivalent conventional design. According to the rules of equivalent outer protective structure's maximum deformation, the feasibility of the equivalent method was studied. Through analyzing three important parameters:pit toe coefficient(χ), the area ratio of inside and outside(α), the depth ratio of inside and outside(β), a formulas is derived to calculate PIP's equivalent design depth.
Using of Seismic Dilatometer(SDMT) for Liquefaction Estimating
Xie Kai, Zhu Dinghua
2012, 26(2): 70-73. doi: 10.3969/j.issn.1007-2993.2012.02.004
[Abstract](45) [PDF 759KB](7)
Abstract:
The seismic dilatometer (SDMT) is a combination of the standard DMT with a seismic module for measuring the shear wave velocity VS. This paper summarized and presented a comparisons of VS measured by SDMT and by other methods. It also illustrated the liquefaction potential of sands based on SDMT results and the applicability of SDMT in Nanjing area.
Effect Analysis of Sandy Foundation Treatments in MU US Desert
Men Qingbo, Xia Yuyun, Wu Xinghui
2012, 26(2): 74-77,85. doi: 10.3969/j.issn.1007-2993.2012.02.005
[Abstract](38) [PDF 747KB](7)
Abstract:
In the research, some field tests on different groud treatments of sand, including water-treatment (hydrostatic deposition process and Water saturated layered rolling process), vibroflotation and dynamic consolidation were carried out to aeolian sands Subgrade in southern fringe of Mu Us desert. According to these test data, this paper had analyzed the changes on physical characteristics and carried capacity of aeolian sand foundation under different ground treatments. Then it summarized the advantages and disadvantages of different ground treatments for aeolian sand foundation, and discussed the function mechanisms of different treatment methods.
Monitoring and Numerical Simulation of Analysis on Deep Excavation of Subway
Liu Yuetao, Yang Huawei
2012, 26(2): 78-81. doi: 10.3969/j.issn.1007-2993.2012.02.006
[Abstract](44) [PDF 717KB](3)
Abstract:
Because of the complexity of ambience and the construction of city subway, foundation pit excavation can cause disturbance to the soil, and bring damages to the buildings and underground pipes, even the stability of foundation pit can be lost. Based on the project of a deep pit,with the aid of FLAC3D, established the foundation pit excavation calculation model. The results showed that the calculation model can simulate the actual excavation process. By the change of model parameters, The author Summarized the influence of the retaining piles stiffness,the retaining system force and deformation, and drew some useful conclusions, and ensured the city deep foundation pit excavation and retaining structure security.
Experimental Study on the Back Pressure Saturation Method by GCTS Hollow Cylinder Apparatus
Wang Tenghui, Zhao Ruibin, Zhang Yan
2012, 26(2): 82-85. doi: 10.3969/j.issn.1007-2993.2012.02.007
[Abstract](45) [PDF 630KB](4)
Abstract:
GCTS Hollow Cylinder apparatus is the best tool to study the soil behavior under the principal stress rotation. In the whole process of torsional shear test, saturation of specimen is prerequisite and the success of the samples saturated also is the key. Taking GCTS hollow cylinder apparatus as a testing platform, the back pressure method is used to saturate hydraulic fill fully. The apparatus provides 3 ways to increase confining pressure and back pressure, i. e. manual stepping, automatic stepping and continuous ramping. Through some experiments, each compression of the corresponding parameters reasonable is explored. 15kpa differential pressure be adequate for hydraulic fill. The standards of pore pressure stability.. If the changes of porepressure in one minute is less than the 5%of difference between the cell pressure and the back pressure, the pore pressure is considered stable.
Engineering Characteristics of Filling Subgrade With Phyllite in Fault Fracture Zone
Lu Daohong
2012, 26(2): 86-89,109. doi: 10.3969/j.issn.1007-2993.2012.02.008
[Abstract](48) [PDF 672KB](3)
Abstract:
After the ‘5 ·12’ Wenchuan earthquake, Phyllite in the fault zone of the Beichuan County was used as the subgrade fill, and tests were conducted on the chemical composition. Physical property and slaking of the fractured Phyllite. Results showed that Phyllite can be used as the bottom fill of the subgrade, and its point load strength is correlated to many factors. Durability of slaking much depends on the contents of clay mineral of the fractured Phyllite, and compaction property is closely related to the relative of different particle sizes. According to the monitoring data on site, the compaction process determined by research can obtain a expected density of Phyllite and improve the physical and mechanical properties of the rocks, which meets the requirements of the subgrade.
Technology Probe and Research
Using Prestressed Concrete Pipe to Test the Grouting Reinforcement Effection
Li Lianying, Wang Zhiqiang, Zhang Xuefei
2012, 26(2): 90-93. doi: 10.3969/j.issn.1007-2993.2012.02.009
[Abstract](31) [PDF 675KB](7)
Abstract:
There are many existing security risks of buildings in the new backfill pit. By using the grouting technologies to reinforce density,uniformity and bearing capacity, we can produce large settlement and uneven settlement in order to problem of negative skin friction of pile, and through the prestressed concrete pipe to test grouting effect in and outside the pit. The results showed that, the character of fill is improved obviously after grouting reinforcement. So, using grouting technology to treat fill is reasonable.
Experimental Analysis on Bearing Capacity of Post-Grouting Simplex Pile
Jiang Ping, Lu Wenzhe
2012, 26(2): 94-97. doi: 10.3969/j.issn.1007-2993.2012.02.010
[Abstract](37) [PDF 628KB](8)
Abstract:
Based on a post-grouting engineering and comparisons of static loading tests (some is post-grouted and the other not). The author analyzed the laws of bearing capacity and settlement, then provided some beneficial references to similar engineering. Post-grouting can increase the bearing capacity of the side and bottom resistance, decreases the settlement of pile effectively. The grouting pressure is a changing value within certain limits, the maximum grouting pressure become greater as time changes. The piles are harder post-grouted and with more grouting pressure. The parameter of these piles should be en sured by field experiments.
Design for Highway Tunnel in Cold Region
Wang Yong, Sun Caihong
2012, 26(2): 98-101. doi: 10.3969/j.issn.1007-2993.2012.02.011
[Abstract](33) [PDF 774KB](3)
Abstract:
Taking some highway tunnels in cold regions as background,The author introduced relevant construction con ditions,structure designs and related calculations. And the special plans on water-proof, drainage and thermal insulation sys terns,It intend to offer guidances and references for simjliar projects.
Monitoring and Numerical Simulation of Analysis on Deep Excavation of Subway
Liu Yuetao, Yang Huawei
2012, 26(2): 102-105. doi: 10.3969/j.issn.1007-2993.2012.02-012
[Abstract](33) [PDF 640KB](5)
Abstract:
Along with the fast pace of urbanization,the protection of historic buildings draw lots of attention in the city. Deep soil excavation engineering in the city will inevitably affect the surrounding historic buildings.Combined with the Tianjin area deep excavation engineering examples,this paper analyzed the failure mechanism and considered uneven subsidence is an important reason.Also,according to the monitoring results,The author analyzed the deformation law in Tianjin region,and discussed the measures to decrease the building deformation.The results can provide a reference for other similar projects.
Ground Treatment Application of Cement Deep Mixing Pile in Municipal Waste Landfill
Liu Gang, Tai Yunhao, Hua Wei
2012, 26(2): 106-109. doi: 10.3969/j.issn.1007-2993.2012.02.013
[Abstract](35) [PDF 815KB](7)
Abstract:
Cement deep mixing is rife method in soft clay foundation treatment, which is frequently applied in ground treatment of saturated clay and powdery soil. This paper introduced ground treatment of cement deep mixing pile in municipal landfill project. This ground treatment heightens the value of suhgrade bearing capacity, and reduces the displacement of foundation soils, and ensures the stabilization of waste stack and foundation soil.

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