Study On Development Characteristics And Perniciousness Of Land Subsidence And Ground Fissure In Beijing Section Of Beijing-Shenyang Passenger Line

Beijing section of Beijing-Shenyang passenger line was dedicated in the northeast area of Beijing, primarily passing through the plain area and mountainous area in northeast of Beijing. Along the line, different terrains varied, complex geological conditions and structures appeared, undesirable geological structures, special rock and soil developed, engineering geological problems widely existed and their influence were widespread. In the plain area, the railway ran through critical land subsidence and ground fissure developed area in Beijing, which resulted in many home damage and road subsidence along the line. Therefore, systematic study on development characteristics and perniciousness of land subsidence and ground fissure along the line was the top priority to guarantee the railway construction and operational safety.In this paper, development characteristics of land subsidence and ground fissure in Beijing section of Beijing-Shenyang Passenger Line were detailed studied and evaluated. The railway run across Gaoliying ground fissure at DK35+888, the main controlling condition was Huangzhuang~Gaoliying ground fissure, predisposing factor was land subsidence, the degree of development was restricted by soil medium and effected by geomorphologic environment. Now, the ground fissure is still active, have a tendency to long-term activities. In this paper, trisection methods was used to classify the structure influence zone, and accordingly to divide ground fissure zone. DK35+778-DK35+927 section of Gaoliying ground fissure belong to danger zone, potentially dangerous was large on both sides of the fracture within 1000 m range. DK21 passed across Shunyi fracture, DK28 passed across Nankou –Shunhe fracture, and the line passed across active fracture, potentially dangerous was large on both sides of the fracture within 1000 m range. DK54 passed across North-Xiaoying fracture, land subsidence development was weak, and North-Xiaoying fracture was secondary fracture, potentially dangerous was little on both sides of the fracture within 1000 m range.Beijing section of Beijing-Shenyang passenger line passed across land subsidence area of Balizhuang in eastern suburbs-Taihu in Tongzhou district, Laiguangying-Jinzhuan in Chaoyang district and Shahe-Baxianzhuang in Changping district. Through long-term monitoring, main features of land subsidence along the line was analyzed and summarized with large amounts of data, and assessed and classified the railway engineering with the speed of more than 200km/h which suffered geological hazard according to "Technical Code for Assessment of Geological Hazard"(draft) issued by the Ministry of Land and Resource. Land subsidence developed strongly near section of DK10~DK38, perniciousness of land subsidence was large. Section of DK38~DK70 was outside the center and sphere of influence of land subsidence, possibility of suffering land subsidence was relatively low, the degree of land subsidence development was medium, and the perniciousness of land subsidence disaster was medium.The research achievement of this paper not only provides basis for the planning and design of the Beijing section of the Beijing-Shenyang railway, but also further enrich the formation mechanism and perniciousness evaluation system of land subsidence and ground fissure in Beijing area, has theoretical significance and practical value.