Loess Collapsibility And Mechanical Properties Of The Pilot Study

The loess is a special soil and distributed widely over our country. Because of its exceptional formation condition, the loess has a lot of special physical and mechanical behavior. Sowemusta ttach p articular importance t o i t i n e ngineering practice. O therwise engineering accidents will happen and enormous losses will be caused.This paper carries out a series of moistening(drying) collapsible tests on intact and tact loess located in Guanzhong area and analyzes the coefficient of collapsibility at different primitive water content in Longxi and Longdong area. This paper also draws some conclusions that the coefficient of collapsibility reduces with the increasing of water content and the coefficient of collapsibility of tact loess is bigger than the intact loess. The loess in Guanzhong area is tested through big and small circular knife, lateral and vertical single lines and double lines. Based on the test data, some instructive conclusions are drawn: the coefficient of collapsibility of big circular knife is bigger than the small; the coefficient of collapsibility of lateral is bigger than the vertical; the coefficient of collapsibility of single or double lines changes randomly but the coefficient of collapsibility of double lines is usually big. The coefficient of re-collapsibility of loess and dealt with acid or dipped in acid is studied more. Through saturated compression test, the structural strength of Longxi loess is smaller than Guanzhong loess, this is also a reason causing the sensitivity of collapsibility of loess in Longxi area is bigger than the loess in Guanzhong area.Finally the properties of mechanics of loess is tested, water affects the shear s trength remarkably, with the increasing of water content, internal cohesion C reduces quickly, but the internal friction angle φ changes very small, but with the increasing of primitive saturated pressure, the internal friction angle φ increase obviously, but the internal cohesion reduces gradually, the difference of anisotropy shear strength is small.