2018 Vol. 32, No. 2

Development and Creation
Application of New Type of Pile Anchor Retaining Structure in Deep Foundation Pit Support in Expansive Soil Area of Chengdu
Jia Xinyuan, Yue Dachang, Li Ming
2018, 32(2): 55-58,99. doi: 10.3969/j.issn.1007-2993.2018.02.001
Abstract:
In the design of foundation pit support in expansive soil area, the conventional pile anchor support system is greatly limited. This paper takes a deep foundation pit supporting project in expansive soil area of Chengdu as an example,according to the characteristics of this project, considering safety, economy, efficiency, environmental protection and other factors, the mechanical expansion anchor pulling pile retaining structure is finally determined, and the scheme selection, support parameter, calculation and analysis process is described in detail.Finally, the monitoring results of the verification, the new retaining structure can adapt to the special geological conditions of expansive soil good and complex surrounding environment, has excellent popularization value and provide some reference for the construction of similar projects in the future.
The Application of Leakage Detecting and Research about Flowmeter Radio-detection, and Correlator in Complicated Environment
Fan Zhiming, Ma Jianguo
2018, 32(2): 59-63. doi: 10.3969/j.issn.1007-2993.2018.02.002
Abstract:
The article takes the combination with the domestic portable ultrasonic flowmeter, radio-detection, and correlator in complicated environment; introducing the theory and use about the portable ultrasonic flowmeter, the theory and use about the radio-detection, and the choice of main parameter on the correlator; solving the difficulties ever met. At last, there is going to state the way how to use the flowmeter and the correlator.
Application Test on High Pressure Jet-grouting Anchor Cable in Soft Soil Area
Liu Kui, Xu Longshuai, Gao Luhao
2018, 32(2): 64-68,109. doi: 10.3969/j.issn.1007-2993.2018.02.003
Abstract:
In order to study the application effect of high pressure jet-grouting anchor cable in soft soil area, three kinds of different fixed anchor length and different number of anchor plate jet-grouting anchor were selected to carry tension experiment to analyze the test result in soft soil area.It was found that high pressure jet-grouting anchor cable had greatly increased the pulling resistance and anti-deformation ability. By using two anchor plates,the ability of anti-deformation has improved significantly compared with using one anchor plate.Under this experimental condition,by increasing the anchor age length of high pressure jet-grouting anchor extension to improve its anti-deformation ability is not obvious.It is of great significance for the application for high pressure jet-grouting anchor in soft soil area.
Technology Probe and Research
Stability Analysis of Slurry Trench of Diaphragm Based on Strength Reduction Finite Element Method
Meng Deping
2018, 32(2): 69-73. doi: 10.3969/j.issn.1007-2993.2018.02.004
Abstract:
Based on the strength reduction finite element method, the stability of slurry trench of diaphragm in the Beijing metro line 6 Xiyuan station was analyzed. The location and profile of the critical slip surface were calculated. The failure process was also simulated in the commercial software ABQUS. Meanwhile, the effects of various factors such as mud weight and depth, underground water level and surface distributed load were provided in this paper.
Global Optimization Stability Analysis of Waterless Homogeneous Slopes-with Integral Method of Circular Slip Surface
Liu Dahai
2018, 32(2): 74-78,82. doi: 10.3969/j.issn.1007-2993.2018.02.005
Abstract:
With the traditional slices method, it requires recalculating the geometric parameters of the soil slices when searching the sliding surface, leading to large calculation workload. It's also difficult to ensure that the sliding surface obtained from searching is the global most dangerous one. In this text, the global optimization software of 1stOpt is used as the tool. Based on the circular slip surface integration method, Fellenius and simplified Bishop analysis methods are used to search the global most dangerous sliding surface of the waterless homogeneous slopes. The results are very satisfactory.
Quick Repair Method of Local Collapse of Embankment Area Using Waste Tires
Liu Jinlong, Zhu Lei
2018, 32(2): 79-82. doi: 10.3969/j.issn.1007-2993.2018.02.006
Abstract:
A quick repair method of local collapse of embankment area using waste tires is proposed in this article, which mainly using waste tire heavy blocks and I-beam. Waste tire heavy block is made by reinforced concrete poured into the waste tire interior space, with low price and simple production. The protection structure of embankment slope assembled by waste tire heavy blocks and I-beams has the advantages of high overall strength, high stability, simple and convenient construction, fast construction speed, and meets the urgent needs of embankment collapse repair.
Analysis on Protection Mechanism and Comparison on Protection Methods for Expansive Soil Slope
Ding Guoquan, Yuan Junping
2018, 32(2): 83-87. doi: 10.3969/j.issn.1007-2993.2018.02.007
Abstract:
Expansive soil is a kind of widely distributed and hard treated trouble soil. Slope failure may often occur in expansive soil. The best slope protection method of expansive soil slope can only be found, if the failure mechanism is considered. Existing research results of slope failure mechanism for expansive soil is summarized in this paper, and the special slope failure mechanism distinguished expansive soil from common cohesive soil is proposed, which is the crack developed in expansive soil, so special attention should be paid to it. The protection mechanism of expansive soil slope is analyzed, which is controlling slope soil water and limiting crack development. According to the difference in protection mechanism, existing expansive soil slope protection methods can be classified to two categories:limiting crack developing methods and non-limiting crack developing methods. The former includes geomembrane method, replacement method, chemical modified method and so on. The latter includes supporting structure method, surface protection method, soilbag method, physical improvement method and so on. Specific analysis and comparison is made for expansive soil slope protection methods, which can be as a reference in engineering application. In the end, suggestions are proposed for slope protection methods designing of expansive soil.
Deep Foundation Pit Slope Displacement Mutation Causes and Treatment Measures Reliability Analysis
Su Tiezhi, Ma Shimin, Wu Min
2018, 32(2): 88-91,95. doi: 10.3969/j.issn.1007-2993.2018.02.008
Abstract:
Foundation pit excavation is a foundation engineering and underground engineering construction of an important subject, belongs to a comprehensive geotechnical engineering problems, not only involves the strength and stability of the typical soil mechanics problems, but also contains the deformation and retaining structure and soil interaction issues. With the development of a large number of urban construction, the more and more deep foundation pit engineering, foundation pit digging ever deeper, engineering geological conditions and foundation pit surrounding environment more and more complex, has caused more and more pit accidents. Each kind of supporting technology and design method is based on certain assumptions, such as the formation parameters, the physical model, boundary conditions, etc. But in fact, the geological conditions are complex and changeful, supporting mechanism is not a pattern, there are many uncertain factors in the construction process, with the passage of time,some factors are still changing. Problems of a certain link may cause displacement of foundation pit slope overrun, threat the stability of foundation pit itself and threaten the safe operation of the surrounding buildings, such as the emergency disposal measures are not timely, not when, is likely to cause serious accident. This paper takes Beijing a pile anchor support of foundation pit engineering as an example, the cause of the foundation pit slope deformation induced overrun and control measures are analyzed and summarized.
Study on Improving the Performance of Gravel Soil by Using the Flow-tube Grouting
Zhai Yuxin, Qi Jianmin
2018, 32(2): 92-95. doi: 10.3969/j.issn.1007-2993.2018.02.009
Abstract:
Pray of molten steel pipe grouting soil improvement, bear the function of load, also can improve the permeability of soil properties, in the foundation pit and edge (slide) in slope supporting engineering application more and more.Its main applications include sustain tension steel anchor pipe and spray of molten steel pipe pile under lateral load, and in the construction process caused by grouting pile soil properties change less attention. In this paper, based on a certain foundation pit project of Fengtai, do the sleeve valve tube grouting in the gravel soil, compared before and after the change of the soil parameters, grouting reveals the grouting reinforcement effect of soil, provide reference for later engineering application.
Characteristics Analysis of Geotechnical Engineering Investigation for Urban Rail Transit
Li Zhengkun
2018, 32(2): 96-99. doi: 10.3969/j.issn.1007-2993.2018.02.010
Abstract:
Complex surroundings, wide content and pertinence for geotechnical investigation, multiple special parameters, diversity of prospecting methods and solutions, etc., are typical characteristics of geotechnical engineering investigation for urban rail transit construction. In this paper, generalization and analysis have been done to illustrate those features, underscored through the example of construction project of Suzhou rail line 5 at western side.
Application and Research of SMW Pile in Deep Foundation Pit Engineering in Soft Soil Area
Yan Yuanyuan, Wang Tao
2018, 32(2): 100-103. doi: 10.3969/j.issn.1007-2993.2018.02.011
Abstract:
Based on engineering example, the mechanical behavior and performance of SMW piles in different excavated deep foundation pit in soft soil area are studied. Differences between measured and calculated values are analyzed. And the optimization suggestions and precautions during the design and construction are put forward. Reference for similar deep foundation pit is provided.
Application of Statistics in Comparative Test at Geotechnical Laboratory
Li Shu, Yu Hongmin
2018, 32(2): 104-109. doi: 10.3969/j.issn.1007-2993.2018.02.012
Abstract:
In order to analyze results of geotechnical test in comparison between operatives, apparatuses, and laboratories, select common parameters such as z-score,bias estimation and percentage relative difference based on mathematical statistics, which makes it possible to evaluate reasonability of physical and mechanics properties index of rock and soil, in the case of lacking the relevant specification.