Study On Surface Rupture Width And Construction Sites’ Security Avoidance Distance Of Wenchuan Earthquake

Longmenshan area, situated between Qinghai-Tibet Plateau and Sichuan Basin whichbelongs to east part of Northwest Sichuan Plateau, is located in the east edge of theQinghai-Tibet Plateau that is formed by the Indian plate and Eurasian plate crashed with eachother. In respect of tectonic settings, Longmenshan stands in a special binding site which isdemarcated by deep faults. That’s to say, the west of Longmenshan is connected withSongpan-Garze geosynclinal area seated in the Central Tibetan Plateau, and the east ofLongmenshan is placed to Yangtze Platform, and the north of Longmenshan joins Qinlinggeosynclinal area. Namely, Longmenshan area attracts so many researchers for its specialvalue and great importance, in addition, the main reason is that Longmenshan area lies themidpiece of north-south seismic belt. From NW to SE the fractures are LongmenshanHoushan fracture, Longmenshan Central fracture, Longmenshan Houshan fracture andShanqian buried fracture. Seriously, the Wenchuan M8earthquake occurred inthe Longmenshan fracture zone in May12,2008.The surface rupture caused by the active fault is the most important geologicalphenomenon, especially the bedrocks near the active faults are suddenly ruptured will causethe overlying soil layers deformation and desolation, which is the most serious area ofearthquake disaster. Earthquake will cause severe damage to the roads、constructions andother human construction projects, cause serious harm to human life and property safety nearthe areas that is crossing the active fault. Therefore, when active fault occurs in construction,we need to determine a safety distance between the construction site and active fault, andprevent construction project from being destructed in the earthquake, which will protect thesafety of human life and property.This article chooses the main street of Xiaoyudong town、nursing home in Hongkoutown Bajiaomiao and the silicon company in Shuimo town wherehas typical characteristics and significance of surface rupture as study model for finiteelement numerical simulation. Through data collection, field investigation and analysis ofgeological process, the failure models of the three typical sites can be determined. With thehelp of ANSYS, the trace analysis for stress and deformation shows the influence of rock’sphysical and mechanical property,thickness and fualt’s angles to the surface reputure.The main conclusions drawn from this thesis are as follows: the stress field’s status of three sites with each condition during earthquake are summarized; Based on Mohr-Coulumbcriteria, the destruction of soil in this site under different conditions during earthquake can bejudged with the results; According to the subjects of numerical simulation, the minimumavoidance distance in three sites under various conditions can be analyzed, and also the strongdeformation zone, medium deformation zone and weak deformation zone can be divided，which will be adopted to determine the security avoidance distance. All of the givenconclusions can pride a primary basis for the planning and designing of local constructionprojects.