A Study On The Law Of Permeability And Collapsibility Deformation And Evaluation Of Collapsible Of Big Thickness Loess Collapsible Under Over Burden Pressure

With construction projects of the Northwest Loess region growing, especially in the thick layer of collapsible loess, ground handling charges huge and needs long construction period. Large thickness of the collapsible foundation deformation and evaluation, processing depth and the reasonable control of residual collapse settlement issues troubled engineering staff Loess. Therefore, the further study of large thickness of collapsible loess provides theoretical design basis for the design and foundation treatment.Based on large thickness collapsible loess field of large-scal water immersion test on site, it adopts the automatic acquisition instrument and transmission equipment and other advanced apparatus for dynamic acquisition of data for TDR soil moisture probe and tension meter which were embedded at different positions and depths, It obtained the volume of soil water content curve at corresponding different depths in monitoring period, and studied the law of infiltration in the loess on the ground after flooding, at the same time it analyzed collapsible characteristics and rules of large thickness collapsible loess from volumetric water content curve of different depths ,the results showed that: TDR soil moisture probe can be used to determine whether the occurrence of collapse deformation,collapsible coefficient of sensitivity and the variation with depths;In water immersion test in situ, using high-precision water level, basicly following the time which is required to specifications, we observed points on land and deep observation points for settlement measurement . It is obtained the settlement curves and sedimentation rate curves of the corresponding location inside and outside the soaking pits during the monitoring period,and the corresponding settlement of soil of different thickness and the corresponding curves were aiso obtained, It was analysed collapsible characteristics and deformation of large thickness collapsible loess without water seepage hole;In addition, the undisturbed soil samples were taken from top to bottom through the same wells, and using the modified stress-controlled triaxial compression and one-way consolidation apparatus , the collapsible coefficient in different conditions were measured , combined with the hierarchical settlement data in situ collapsible water immersion test , comparing collapsible deformation at different experimental conditions, the law of collapsible deformation was analyzed, and the collapsibility evaluation method was preliminaryly tried to explore. Results show that: triaxial test can relatively accurate evaluate of collapsibility of loess.