Study On Hunhe Fault Zone Activity And Disaster Effect

The Hunhe fault is an important branch fault in the northern extension of the Tanlu fault zone.The fault extends far and has a large cutting depth.It extends east-west across Shenyang and Fushun.Its current activity has a major impact on urban planning and engineering construction safety.The thesis relies on the "Shenfu New Area Active Structure and Geological Survey" project of the China Geological Survey,through on-site surveys and explorations,combined with existing literature achievements,to obtain the following main results and understanding:(1)The Hunhe fault is a branch fault in the northern extension of the Tan-Lu fault zone,which cuts the lithosphere.It belongs to a deep fault and has a complicated structural background.Under the condition of the horizontal structural stress field in the northeast-northeast direction,the Hunhe fault showed a right-handed strike-slip motion.Since the Neotectonic Movement,the differential settlement activity on both sides of the fault zone is not obvious.(2)The Hunhe fault zone is composed of several main faults and branch faults,which are cut by northwestern faults.The fault zone can be divided into three sections:west,middle and east.Among them,the western section is basically in concealed state,the middle section and the eastern section are in the low mountains and hills.The fault structure and geomorphology are clear.The fault triangle,fault cliffs,fault steep ridges,seismic compression ridges and other structural geomorphology are developed along the fault zone.(3)The results of fault mud luminescence test and cross-fault terrain change monitoring data indicate that the overall activity of the main fault zone of the Hunhe fault is not strong and has segmented characteristics.Among them,the eastern part is the most active,which is Holocene activity;the middle part is followed by the late Pleistocene activity,and the west part is the weakest:it is the early middle Pleistocene activity.(4)The manifestation of the disaster effect of the Hunhe fault is mainly the landslide hazard along the fault zone and the extensive development of ground fissures in the fault zone.On-site investigations and ground deformation monitoring data in the ground fissure area indicate that the disaster-causing effect of the Hunhe fault zone is closely related to the development of pre-existing fault zone structural planes(pre-existing weak fault planes,joint planes,fissure planes,etc.).It is controlled by factors such as the appearance,filling,bonding strength,and spatial combination of each structural surface of the fracture zone.(5)The concealed area in the western section of the Hunhe fault,the old urban area of Fushun is affected by mining activities,and some of the main faults and branch faults of the Hunhe pre-existing weak fault layer(or belt)have been partially opened and expanded,gradually expanding to the surface and finally forming Ground fissure.The pre-existing weak fault structural plane controls the location and distribution direction of the ground fissures,while the tension of the fault zone and the nature of the soil affect the magnitude and deformation mode of the ground deformation on both sides of the ground fissure.(6)In the middle and east of the Hunhe fault bedrock mountain area,the fault zone and the impact zone have structural planes developed,the rock mass is broken,and the surface often constitutes steep ridge landforms.The structural surface along the slope gradually expands and penetrates under the action of long-term rainfall infiltration,forming a sliding surface,which eventually leads to the occurrence of landslides.