Typical Uneven Ground Subsidence Area Beijing-based Research PS-InSAR Technology And Information Entropy

Land subsidence is an environmental geological phenomenon which ground elevation dropped, it get compensation cannot permanent loss of environment and resources Beijing was found to have the ground subsidence since the60’s of last century, the plains presents rapid growth trend. The cause of the land subsidence of Beijing plain is mainly underground resources, especially groundwater overexploitation. However, with the rapid development of city construction in recent years, the high-rise and super high-rise buildings and the static load, dynamic load track traffic form a sharp increase which aggravates Beijing land subsidence in some degree. In different regions of Beijing the groundwater exploitation is different, coupled with the construction group and track traffic distribution also has differences, which lead to regional uneven ground subsidence. Uneven ground subsidence will not only lead to building basement imbalance, induce the collapse of buildings, but also damage the linear rail transportation, underground pipelines, brings the serious economic loss, affects the production, life security of people. However, at present, research specifically for the uneven land subsidence is still in the exploratory stage and most visually oriented.Entropy is the probability of occurrence in discrete random events, it is used to describe the motion of matter degree of disorder and chaos, and it also can be used to study the regional land subsidence difference index. The smaller entropy, the smaller deviation, the weaker uneven land subsidence, which suggests the relative concentration of land subsidence rate in the region; on the contrary, the lager entropy, the greater intraregional differences, the more complex system is, then the rate of land subsidence in the region is relatively dispersed. The process of entropy from0to the maximum, in fact is the process of the region uneven land subsidence degree increases.This paper chooses Beijing Plain region as the study area and uses PS-InSAR technique to acquire the land subsidence monitoring information, we preliminary analysis the spatial character of the land subsidence, on this basis, combining entropy analysis Beijing uneven land subsidence from the quantitative angel on different scales. The results showed that:(1) We used PS-InSAR technique to acquire the land subsidence monitoring information (2010-2013), the results showed that he most serious region land subsidence appeared in Chaoyang and Taihu inTongzhou, the maximum subsidence rate were77.69mm/a and76.1mm/a.(2) On the basis of using PS-InSAR technique to obtain information of land subsidence in Beijing plain, we classified land subsidence data and calculated ground subsidence information entropy. The results showed that entropy in Chaoyang(3.02bit) was the largest, it illustrated in this area the extent of uneven land subsidence was the strongest. The entropy in Taihu(2.69bit) was relatively small, this revealed Taihu has a lower extent of uneven land subsidence. This study has a certain theoretical and practical significance in Beijing uneven land subsidence, and it provided the scientific basis for further control and prevention of land subsidence.