Seepage Deformation Experimental Research Of Fissured Loess

The GNP and economical development are seriously affected by the ground fissures in Fenwei basin, its paroxysmal attack mostly relates to sudden storm. Therefore, to study on the strength and deformation characteristics of submergible loess in the fissure zone assume even greater importance. It can provide a reference to the study on formation mechanism of ground fissure as well as an experience to soil and water loss, disaster preventive measures, engineering properties of loess and some related geotechnical engineering problems.Both of the micro and macro geological characteristics of soil of ground fissure zone are ascertained, the distributions and development laws of ground fissure in the Fenwei basin is detected, water is determined as the external dynamic factor to abnormal activities of ground fissure in the district though the field investigation to the test spot for forewarning and exhibition of ground fissure in Shuanghuai village, Sanyuan country, Xianyang region, the means of tests such as infiltration test through method of double-ring and varying head, three-axial compression test are applied to the micro study. According to those studies, the loess spots which across by ground fissure are taken as examples, the field pit infiltration test is carried out, the properties of infiltration and deformation of loess in the ground fissure zone are researched systematically and deeply theoretical analyzed. The results from the investigation showed:(1) The negative correlation is found between coefficient of infiltration, and the side coefficient of infiltration is lower than that of the vertical at the different depth and width of ground fissure, almost an order of magnitude. The vertical infiltration of Q₃ loess is affected by the ground fissure, the wider the fissure is, the better vertical infiltration is. The side infiltration is less affected by ground fissure; infiltration of Q₂ loess is less affected by the width of ground fissure within the 1cm wide range of ground fissure.(2) Analysis of the strength of the loess of the same type ground fissure zone reduce with the increase of rate of water content, and the negative correlation is also found between the width of ground fissure and loess strength though the analysis on control action of ground fissure width and rate of water content to mechanism characteristics of loess. The deformation of loess can be classified into four types: axial deformation, flexural deformation, rotational deformation and torsion deformation.(3) Though the comprehensively analysis of field water test on section of rate of water content, the subsidence relation at different depth, contour map of the and subsidence, it turns that the existence of ground fissure result in unevenly infiltration in the infiltration field, which arise distinctive subsidence between the soil of ground fissure belt and the soil around. Four causes are found (such as infiltrated draw, water erosion, infiltrated consolidation and drainage consolidation) affect the reduce of different types soil strength with the increase of rate of water content.