The Research On Field Monitoring In Treated Subgrade And Cutting Slope Of Expansive Soil

Expansive soil is a special clay soil, possessing feature of swelling&shrinkage, over—consolidation and fissures. The engineering disaster induced by its ill peculiarity has become the most serious technical problem in NanYou highway. Referring to the expansive soil research project of communication ministry west item, the treatment scheme was presented and the field test project was constructed by Changsha University of science and technology. In order to verify treatment effect , grasp the situation change in subgrade trackly , develop further research on treatment technique and failure mechanism , the research group set many survey section at the test project and cutting slope, carry a field monitoring on the index of moisture temperature distortion nearly two years.Applying the science thought plan of evaluation,interpret,comparison,forecast and extend as Analysis angle , the thesis analysis and research the monitoring data objectivity and comprehensive , get some innovation harvest in the following aspect: (1) put forward the concept of the acute Influence depth of wetting-drying cyclic, through analysis of variation discipline of moisture,temperature and deformation , it can be conclude that the acute Influence depth of wetting-drying cyclic in this region is between 1.8m—2.3m, which is close to the result of formerly research , and it provide reference for engineering treatment.. (2) The three stage of development of slope distortion under the effect of annual wetting-drying cyclic is monitored completely. The location and preferential direction of two Potential landslide surface ,which nearby 3.0m and 6.0m ,are in the hoar expansive soil layer and weathered interface. The landslide of expansive cutting slope is following layer and slope, which according with the result of geological investigation, A half- quantitatively failure Paradigm for landslide of swell& shrink active zone is Proposed. (3) By establishing gray theory GM(1,1) model , make a forecast to relative deformation on surface of slope , comparing with monitoring data, it found that they can be consistent very well at the initial two months , but not satisfy for the succession date. It mainly caused by seasonally difference of deformation.In conclusion, the research on monitoring data in this thesis accord with relative theory and engineering practice, reflect the variation discipline of various physics and mechanicals index actually, describe and forecast the deformation trend exactly. verify treatment effect preferably .It may provide valuable reference for relational research.