The Study On Ground Fissure Extension Direction And The Width Of Its Affected Zone

Ground fissure has become the most serious geological disaster in Xi'an at present. It not only brings about huge economic losses to urban construction over the years, but also restrict the city planning. However, the ground fissure activity receding obviously with the control of exploiting the underground water, the contradiction between the hope of using the ground fissure zone more and the restriction on the existing standard is growing. So that the in-depth understanding of both the happen and the development of the ground fissure has the vital significance to the reduce of the economic losses and also can promote the research and solution to the problem. The purpose of this article is acquiring the general rules of the ground fissure's development including the issue that the ground fissure's extension direction and the upper plate and footwall of ground fissure which can provide reference to the uses of the ground fissure zone.The research idea can be conclude as follows:different thing should have common essence if they have similar appearance. The essence of ground fissure is the fracture of strata. It has commonness with normal faults, and has personality of its own activity Ground fissure has similar appearance with normal faults for the surface exhibit and the vertical form, but they also have differences on the activity level and the periodicity which because of the excessive mining of groundwater. The article use the material mechanics and elastic mechanics theory, based on the monitoring results of ground fissure, with the computer aided of finite element software, analyse it from the statics angle. First of all, the fracture surface has already exists:whether the large-scale fault still the small-scale ground fissure, the footwall has more serious damage than the upper plate, and has larger deformation range. Besides, we analyse the main factors which has relationship with the ground fissure's influence width such as the soil compression modulus, the boundary displacement, inclination of the fracture surface and the section friction. Secondly, the fracture surface hasn't exists yet. We analyse why the tendency of ground fissure fracture surface is opposite to the one of upper building cracks and the reason why the development form of near-surface fissure is multiple. The article put forward that the main influencing factor of the fissure extension direction is horizontal stress, but the diversity control factor of the near-surface fissure is not only the horizontal stress but also the soil mechanics properties. We still talk about the research scale and the analysis precision problem in the article which proved the rationality of the linear elastic to a certain degree.