Analysis of soaking deformation characteristics of large-thickness discontinuous collapsible loess
[Objective]The unique stratigraphic structure of the widely distributed discontinuous loess stratum in the Guanzhong Plain area of China results in significant differences between the indoor calculated values and field-measured values of the self-weight wetting amount for evaluating the foundation's wetting property.[Methods]Indoor wetting tests and large-scale test pit immersion tests were carried out on-site to compare the factors influencing the difference between on-site and indoor wetting amounts,with the loess stratum on the north bank of the Weihe River as the research object.[Results]The following results were obtained from the study:(1)The ratio of self-weight wet depressions between field and indoor test was less than 0.1.This discrepancy was due to the discontinuity and inhomogeneity of loess layers,sampling disturbances in indoor tests,and differing immersion conditions in field test.(2)The"layer bow effect"caused by the discontinuity of loess was the main reason for the difference between the indoor and field tests.This effect weakened upward-transmitted deformation,hindered downward-transmitted gravity stress,and caused discontinuity in the percolation process.(3)Stratification calculations for the four test sites showed that most of the gravitational self-wetting in the field tests occurred in the Qp3 soil layer,while the Qp2 loess layer showed large difference between the field-measured and indoor test values.Thus,the Qp2 loess layer has little to no wetting effect.[Conclusion]The shape of the saturated zone range obtained through numerical simulation was consistent with the field test results,and the numerical simulation method was more advantageous for observing the experimental results.When calculating wet subsidence by self-weight,a stratification method based on the strata age can be used.For the Qp3 stratum,the correction coefficient method specified in the guidelines was chosen,while the Qp2 loess stratum was determined by an on-site pit immersion test.[Significance]The research methodology used in this study provides theoretical guidance for future engineering constructions on the Guanzhong Plain.
collapsible loessin-situ soaking testcharacteristics of collapse deformationloess-paleosol
万方数据
维普
