Xi'an Ground Fissures Of Loess Collapsibility

Ground fissure is the'main geological disaster in Xi'an city construction. Researching the mechanism of Xi'an Ground fissures has an important purport to protect and lighten the disaster effectively. Influence factors of Xi'an ground fissures movement are very complicated. Now, many researchers believe that the movement mode and intensity of the ground fissures are mainly controlled by the Lintong-Chang'an fault and the ground subsidence caused by excessively pumping ground water , especially the differential subsidence on both sides of the ground fissure is the major reason of. intense movement of ground fissures at present. But there is few research on the relationship between the collapsibility of loess and the ground fissures.In this paper, the relationships among the collapse grade and style of loess and the distribution and action intensity of the ground fissures are analyzed. And there is strong homologous relation between the collapsibility of loess and the movement of the ground fissures. They have common characters that moving on the east part of the city is more intensity than that of west part, moving on the south part of the city is more intensity than that of north part. These characters show that there is positive relativity between the ground fissures and the collapsibility of loess.In this paper, considering the action of the surface water filtering along the fissures ,the numeration formula about the amount of collapse on both sides of the ground fissures is established through supposing some parameters. Then the amount of collapse reflected to the ground surface is approximately equaled to the amount of the non-uniform settlement at ground surface on both sides of the ground fissures. That the non-uniform settlement added to the deformation of the ground fissures will enlarge the ground fissure disasters.At last, disaster protection measures for Xi'an ground fissures are simply discussed in this paper.