Research On Soil Permeability Of Xi'an F3 Ground Fractures

Ground fracture is a typical regional geo-hazard, which bring damage to various types of buildings, transportation facilities, city lifeline projects and the land resources.The hazard has brought enormous economic loss to the construction of Xi'an in last several years. Now, Xi'an Subway is under construction. About 15 ground fractures are crossed by the subway, which will bring adverse effect to the subway construction and operation. Therefore, it is a great question of xi'an subway design and construction to solve the structure and Water-proof measure of ground fractures.Based on the fracture hydrogeology test results and previous data of xi'an subway Line 1, which carried on laodonglu school,the geological structure, landscape features, formation lithology and hydrological of the test site are introduced firstly. Then the test plan is designed,which include the layout, structure and the construction technology of the pumping wells and observation hole, the plan of the field seepage test, plan of the precipitation in the first test drilling water and the plan of the pumping test.Secondly,the process of the field seepage test, recipitation in the first test drilling water and the Pumping test are detailed description in this paper. A variety of ways are used to arrange and analyse the test dataThrough the pumping test,the permeability coefficient of the fracture zone is the largest,the under plate of the fracyure is the second,the upper plate of the fracture is the leastThe water contact of the both sides of the fracture is weak.the water Supply source of the both sides may be different.Finally, analysis are carried on the results of the hydrogeological test through several ways.Through the research on the physical and mechanical properties of rock and soil of the fracture,we can found that the difference of the physical and mechanical properties of rock and soil between the two sides is small,the break of the Aquifer cause the weak of the water contact between two sides of the fracture,The infiuence of the building imposed on the upper side of the fracture is simulated by using 2-D finite element software in this paper, and the results show that the load caused change of the Soil properties,which is imposed on the upper side of the fracture by the building, influence the test results,cause the water supply become difficult and the permeability coefficient is smaller.