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Construction Disturbance Effect Of Soft Soil Ground Improved By Vertical Drains With Probability Analysis

Posted on:2007-09-15Degree:MasterType:Thesis
Country:ChinaCandidate:W WangFull Text:PDF
GTID:2132360182971866Subject:Municipal engineering
Abstract/Summary:PDF Full Text Request
One of the effective ways of soft clay ground treatment is using vertical drains. The process of vertical drain construction leads to push stress around the soil, loss in soil strength, decrease in bearing capacity, and great influence on the stablization and settlement of the ground. Based on the theoretical analysis of the disturbance effect during vertical drain construction, in this paper, probability analysis is adopted, and the impact of variability of parameters with larger uncertainty or discreteness on consolidation reliablity is analyzed, which is very useful in the design and construction of soft clay ground treatment. All the work done is as follows:Firstly, given the impact of the soil gravidity stress on the scale of the vertical drain disturbance, Vesic's column cavity expansion theorem is mended. Then the radius of the plastic zone, the ultimate crowding stress and the soil displacement in the intersection of plastic and elastic areas are deduced when Mohr-Coulomb surrender criterion is adopted. The result of which caters better to the real situation. Based on the above, the relationship between the disturbance area and the plastic area during the vertical drain construction is discussed, combined with project cases.Secondly, the impact of the variability of parameters with greater uncertainty or discreteness on the vertical drain ground consolidation is analyzed through statistical moment method. Based on Rosenbluth's 2-point estimate method, further research is done on the application of multi-point estimate method, which is more accurate in the probablity analysis of the vertical drain ground consolidation. As to parameters with nonnormal distribution, Rosenblatt Transition is adopted in order to improve the accuracy. At the same time, parameters with unknown distribution are also considered in this paper, which are analyzed through three order moment standardization method.Thirdly, the reliability of consolidation of the vertical drain ground is analyzed, then the probability limit equation is formed, so is the general process of the reliability through statistical moment method.Finally, according to project data of Xuyang road Embankment, the parameters which affect the vertical drain ground consolidation are analyzed, one time the reliability level of achieving target degree of consolidation, as well as various time the settlement credibility intervals under a probabilistic level, is computed through statistical moment method. Then the results are compared with Monte-Carlo methods. Case analysis indicates that, the statistical moment method with multi-point estimate mathod is not only brief but also accurate, so it can be widely applied in projects.
Keywords/Search Tags:soft clay ground, consolidation, vertical drain, construction disturbance, column cavity expansion, probablity analysis, statistical moment method, reliability
PDF Full Text Request
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