岩土工程技术

Analysis of Ultra-high Slope Supporting Design Adjacent to Existing Tunnel

Huang Chengzhong

2015, 29(3): 109-113. doi: 10.369.j.issn.1007-2993-2015.03.001

[Abstract](39) [PDF 1413KB](14)

Abstract:
It may make the design unsafe when the Technical Code for Building Slope Engineering GB 50330 are directly used in ultra-high slope, especially when the building adjacent to the ultra-high slope, as the design parameters, the resultant and distribution of the lateral pressure are special. Taking a ultra-high slope adjacent to existing tunnel as an example, a method is presented to solve the supporting security which concluded analysis of slope failure modes and problems of use the current code, and the current code and the results of the above analysis are used to design the ultra-high slope supporting, then the deformation law of ultra-high slope and existing tunnel are analysed by use of numerical simulation method. Safety and rationality of the solution method and design idea are validated by monitoring results, which can provide a reference for similar ultra-high slope.

Research on Water-physical Properties of Rock Similar Materials

Xiao Jie, Liu Baoguo

2015, 29(3): 114-117. doi: 10.369.j.issn.1007-2993-2015.03.002

[Abstract](38) [PDF 882KB](8)

Abstract:
The similar material made by cement, plaster and sand in certain ratio situation did not disintegrate when they met water, whereas they softened like rock. By the similar material proportion test at different sand-binder ratio and cement-plaster ratio, this paper summarized the changing rules of softening coefficient and water-absorption affected by sand-binder ratio and cement-plaster ratio. The softening coefficient of similar material reduced as the sand-binder increasing whereas ascended as the cement-plaster increasing and the variation range was similar with real rock. The water-absorption of similar material ascended as the sand-binder increasing whereas reduced as the cement-plaster increasing and it was larger than the water-absorption of real rock.

Three-dimensional Numerical Simulation Study of CFG Pile Composite Foundation Settlement

Zhou Chen, Li Baoqiang, Wang Jian

2015, 29(3): 118-121,131. doi: 10.369.j.issn.1007-2993-2015.03.003

[Abstract](34) [PDF 1922KB](16)

Abstract:
Through field test data and the data existed, the article uses FLAC-3D software to simulate and analyze the mechanism of CFG pile composite foundation settlement laws proposed high-rise buildings and underground garage space, as well as the role of the relationship between the two in terms of the deformation of the building. The obtained data is compared by simulation of settlement of CFG pile deformation and actual measurement, which obtained the actual CFG pile settlement distribution,has the instruction significance to the design of CFG pile composite foundation under similar conditions.

Research on Foundation Bearing Capacity Calculation Methods of CFG-Pile Composite Foundation

Zhang Qinxi, Wang Xiaojie, Tao Tao

2015, 29(3): 122-126,162. doi: 10.369.j.issn.1007-2993-2015.03.004

[Abstract](38) [PDF 967KB](9)

Abstract:
CFG-pile composite foundation as an economy convenient effective ground handling means has been widely used in engineering field. For the calculation of bearing capacity of composite foundation of CFG pile, we analyses the not uniform on provision and too conservative on calculation about bearing capacity of composite foundation in Technical Code for Ground Treatment of Buildings and Code for Design of Building Foundation. Based on the theory of traditional Terzaghi and practical experience in engineering,propose the new method which correct the soil bearing capacity between piles firstly, then assemble the bearing capacity of pile and soil.

The Research on the Treatment of Soft Soil Foundation's Bearing Capacity Through Vibro Replacement Stone Pile

Li Xiangqun, Yang Fengnian, Wang Haipeng

2015, 29(3): 127-131. doi: 10.369.j.issn.1007-2993-2015.03.005

[Abstract](38) [PDF 1280KB](13)

Abstract:
The vibro replacement stone piles are widely used in engineering and various problems have been studied in different depth. Based on the soft soil foundation treatment of vibro replacement stone pile, combined with super heavy dynamic penetration test,dynamic penetration test results, we can get parameters and we can know that vibro replacement stone piles deal with soft foundation can improve the foundation bearing capacity of composite foundation, modulus of deformation and reduce settlement. Engineering practice shows that the method of soft foundation treatment with economic reasonable, convenient construction, fully meet the design requirements and can be widely used.

Analysis of the Supporting Effect of Double Row Piles Reinforcement

Fan Jiliang, Liu Xiufeng, Li Jun

2015, 29(3): 132-134. doi: 10.369.j.issn.1007-2993-2015.03.006

[Abstract](139) [PDF 1949KB](17)

Abstract:
The use of cantilever double row piles would cause a larger displacement in Tianjin soft soil area. According to this characteristic, the paper reinforced the soil by cement between the double row piles and then maked the calculation analysis. The results indicated that the effect of reinforcement on foundation pit deformation was obvious. The horizontal displacement of the excavation reduced by 30 %. The horizontal displacement of the double row piles top decreased nearly 40 %.

Theoretical Study on P Factor in Pile Group Effect under Horizontal Load

Wang Jian, Wang Jianhua

2015, 29(3): 135-137,157. doi: 10.369.j.issn.1007-2993-2015.03.007

[Abstract](48) [PDF 762KB](7)

Abstract:
In the pile foundation,when the pile group by is under horizontal force, if the pile group spacing is less than 8 times the pile diameter, pile group horizontal force is not equal to the sum of horizontal force of each pile, through test get smaller value of each pile horizontal force are often used in previous studies. P factor is a typical method of pile groups capacity reaction, but the theoretical research in this area is relatively small, the paper summarizes and analyzes the previous experimental data,makes a summary to the P factor, gets a theoretical formula, the study plays a catalytic role in the horizontal force of pile group.

Study on Optimum Cross-section of Gravity Retaining Wall

Hu Xiaoping

2015, 29(3): 138-140,143. doi: 10.369.j.issn.1007-2993-2015.03.008

[Abstract](30) [PDF 1076KB](11)

Abstract:
Taking the cross-section area of a gravity retaining wall as the objective function,and considering the stability of anti-sliding and anti-overturning, ground base stress, related construction requirement as restraint conditions, the mathematical model was established. Based on the patternsearch tool of Matlab, the section of the retaining wall was optimized, on the basis of verifying the result, by comparing the result with the existing literature, it showed that the optimization capability of pattern search algorithm was great, the optimization for the section of the retaining wall was realized, the effect was significant, so it can be widely applied in engineering.

Discussion of Sintered Red Mud's Engineering Geological Stratification

Jie Duoling, Niu Junxian

2015, 29(3): 141-143. doi: 10.369.j.issn.1007-2993-2015.03.009

[Abstract](22) [PDF 507KB](8)

Abstract:
In this paper, according to many years in the red mud yard in the stability analysis of engineering practice, based on sintering red mud engineering performance, name of red mud should follow the scene proposed sintering, lithology. And water problems directly affect the degree of consolidation of red mud, and the specific engineering geological stratification method is given.

Discussion about the Prevention Measures of Geological Collape Hazard of Laoshan Scenic Spots in Qingdao——Take a Regulation Project of Dangerous Rock Collapse in Dapinglan as an Example

Li Yuwen, Wang Nini, Zhu Ming

2015, 29(3): 144-148,152. doi: 10.369.j.issn.1007-2993-2015.03.010

[Abstract](26) [PDF 6727KB](9)

Abstract:
Collape is the main type of geological hazards existing along the Laoshan scenic spot, which is needed to control by scientific effective measures. The existing regulation projects of collape hazards in Laoshan are mostly adopted clearance, reinforcement and retaining wall. These measures can eliminate some degree of geological hazards, but the regulation effects are often poor in tourism scenic spots. According to the characteristics of geological collape hazard in Laoshan scenic spot, and insisting on the principle of environmental harmony for engineering effect, there is a first application of flexible protection system (SNS) in Regulation Project of Dangerous Rock Collapse in Dapinglan. The system's good project effect can fully embody the environmental harmony of engineering subject, and it is able to eliminate hidden dangers, at the same time, provide a maximum protection of slope ecological environment and maintain landscape visual aesthetic feeling. To the collape hazard management in Laoshan scenic spot, the SNS system applied in Dapinglan provides a new thought of collapse treatment and a demonstration of engineering example.

Numerical Simulation of Retaining and Protection Structure with Soldier Pile Wall and Single Strut for an Excavation

Li Ziwei, Liu Chun, Meng Xiujing

2015, 29(3): 149-152. doi: 10.369.j.issn.1007-2993-2015.03.011

[Abstract](34) [PDF 880KB](9)

Abstract:
By using the finite element software, Plaxis, HS soil constitutive medol is adopted to simulate of R & F Guangdong Building in Tianjin. The monitoring and numerical simulation analysis show that supported by the soldier pile wallsrut can effectively limit the lateral displacement of excavation. The numerical results agree with the monitoring data. It is helpful to use the Plaxis for the design and construction of excavation.

The Research to the Bearing Capacity of Sand and Gravel Stratum in Shenyang Area

Liu Xu, Shu Zhaoran, Liu Zhongchang

2015, 29(3): 153-157. doi: 10.369.j.issn.1007-2993-2015.03.012

[Abstract](30) [PDF 993KB](14)

Abstract:
There buried rather thick upper Pleistocene series Q3 stratum in Shenyang area, including medium, coarse sand, gravel sand and round gravel, these stratums have stable distribution and biggish bearing capacity to be the foundation bearing stratum of high-rise structure, but not yet to use the bearing capacity more fully. This paper exploit the bearing capacity of sand and gravel in Shenyang through test and experiment of several typical projects, and give the available range of the bearing capacity characteristic number and deformation modulus, providing a basis for the rational utilization of good natural foundation, at the same time, proposes the research direction in future.

Application of Jet Grouting Reinforced Cement-soil Pile-Anchor Support Technology in Deep Foundation Pit Engineering

Tao Zhu, Fan Qinjian, Song Dexin

2015, 29(3): 158-162. doi: 10.369.j.issn.1007-2993-2015.03.013

[Abstract](29) [PDF 1453KB](11)

Abstract:
The jet grouting anchor, a new technology which combines large-diameter cement-soil pile with conventional anchor, is usually applied in the foundation pit support in soft soil. Compared with conventional anchor, it has advantages for large-diameter and high bearing capacity. Then the displacement of excavation can be controlled effectively. Connecting the application of jet grouting reinforced cement-soil pile-anchor during an engineering case, the paper introduces briefly this support technology and analyzes the control effect of pit deformation by monitoring wall top horizontal displacement and the soil deep horizontal displacement. The results show this support form is safe and economic. It could provide references and suggestions for similar projects.

2015 Vol. 29, No. 3