Engineering Properties Experimental Study Bao Lan Of Collapsible Loess

This paper aims to make a systematic study of treasure engineering mechanics of loess and modified cement loess characteristics, through data, literature survey, field sampling and gathering information and indoor and outdoor tests. The conclusions are as follows:(1)Through the physical test for the BAO LAN analysis of loess, the Loess belongs to get sandy loess, grain composition is single, mainly coarse silt.(2)Through the test of mechanical properties of loess is BAO LAN, direct shear test, the basic mechanical properties parameters of three axis test, compression test,permeability test, collapsibility test of loess in the area are obtained. At low pressure(100 k Pa), the sample will happen dilatancy damage; shear strength determination should try to choose three triaxial test of soil; the maximum reached 6.98E-04 permeability coefficient of loess and BAO LAN, the permeability coefficient decreases with the deepening of the soil, dry density increased; BAO LAN loess collapsibility coefficient is less than 0.07 of the peak, belongs to the medium of collapsible loess; and 2~6 m depth soil belongs to self weight collapsible loess(collapsible coefficient greater than 0.015); the increase of initial collapse pressure decreased with soil depth increasing, were less than 200 k Pa.(3)Through laboratory tests on BAO LAN cement improved loess, namely compaction test, unconfined compressive strength test, compression test, direct shear test, permeability test engineering characteristics of BAO LAN cement improved loess. The cement soil and the maximum dry density, optimum moisture content decreased with the increase of cement mixing ratio decreased first and then increased;the compressive strength of cement soil, permeability coefficient, compression modulus, cohesion and cement mixing ratio, degree of compaction, there is a certain relationship between curing age; cement ratio is 10 %, the demarcation point of compaction the degree of K=95 % can be used as cement soil strength attenuation degree; cement soil direct shear test will produce dilatancy effect, and the verticalload is small(100 kPa), dilatancy effect more obvious.(4)Through laboratory tensile tests on BAO LAN cement improved loess,conserved 3 d tensile strength of soil cement with cement mixing ratio, dry density increases and increases; Cement Improved Loess under uniaxial tensile stress failure displacement curve was hardening, damage and show brittle failure, therefore can improve the cement mixing ratio or water reducing rate of cement soil to prevent soil cracks in structures.The last part carries on the preliminary discussion the BAO LAN loess and cement improved loess engineering characteristic,which providing valuable information for the properties of soil in Longxi area, and creating the theoretical basis for the design of similar engineering.