Research On The Influence Of Structural Damage Rock On The Formation Of Debris Flow

Affected by the uplift of the Qinghai-Tibet Plateau and crustal movement,the Anning River fault zone has very strong tectonic activities and frequent geological disasters.Debris flow is the most important geological disaster in the Anning River fault zone,and its most important factor is source of debris flow.This paper focus on control effect of fracture zone structural damage rock mass on the formation of debris flow.conducts field surveys of the geological sections and rock structure characteristics of Anning River fault zone(Mianning profile?Lugu profile).Using the statistics of joint fractures of precision survey control network and joint rock mass density calculation methods.Through the above methods,the development characteristics of joints and fissures in the crustal rock mass in the fault zone can be ascertained,which can reflect the fracture characteristics of the rock mass in the Anninghe fault zone.Based on this,the structural damage zone of the Anninghe fault can be accurately determined.On this basis,we can explore the physical and mechanical characteristics of damaged rock masses in different rock zones by analyzing the strength and hydraulic characteristics of damaged rock masses in structurally damaged rock zones.Then combined with the development and distribution status of the debris flow provenance area in the Anning River fault zone,explore the impact of structural damage rock mass on provenance formation.The main achievements of the thesis are as follows:(1)Based on the survey and analysis of the structural damage and fracture structure of the crustal rock mass of the Anning River fault zone,the structural damage rock zone of the Anning River fault zone is divided into a fracture zone(fault fracture zone),fragmentation rock zone,fracture rock zone and Relatively complete initial background rock zone.From the fault zone to both sides is divided into "Fault fracture zone-Fractured rock zone-Background rock zone".Mianning profile in the northern section of the Anninghe fault zone,Because of the main fault developed into two branches,the entire section is divided into "Background rock zone-Fragmentation rock zone-Fault fracture zone-Fractured rock zone-Fault fracture zone-Fragmentation rock zone-Background complete rock zone" from west to east;(2)Structural damage has a great influence on the strength and hydraulic characteristics of the rock mass.The uniaxial compressive strength and disintegration resistance of the rock mass vary greatly depending on the degree of damage;(3)Tectonic stress-damaged rock belts combined with field geological disaster investigations revealed that the provenance area of large-scale debris flows along the fault zone is mainly developed in broken rock zones(fault fracture zones)and fragmentation rock zone.Among the 18 debris flow ditches in the statisticds,13 of them are located in the Fault fracture zone or fragmentation rock zone,4 are located in the fractured rock zone,and only one debris flow ditch is located in the background complete rock zone;(4)By investigating the development and distribution of the debris flow source area in the Anning River fault zone and the zoning of the structurally damaged rock mass,we can find that the source of debris flow in the Anning River fault zone is mainly controlled by internal dynamic geology.It is also affected by external dynamic geological effects such as stratum lithology,weathering unloading and water action.(5)As the main controlling factor for the formation of provenance,the internal dynamic structure damage causes the rock mass to be strongly broken and the integrity of the rock mass structure to drop sharply.And under the action of external dynamic conditions,it provides a sufficient material source for the debris flow in the study area.The uneven uplift of the earth's crust and the sharp erosion and downward cutting of rivers have greatly changed the air access conditions of the original broken rock mass,greatly increased the gravitational potential energy of the rock mass,intensified the unloading deformation of the rock mass,and significantly reduced the surface The state of self-stability of the rock mass.On the other hand,when the debris flow's provenance area damages the fragmented rock mass in a high-level unloading state,the loose and broken strong unloading and strongly weathered rock mass is combined with the surface water scour of the rainy season and the groundwater runoff field.The probability of a debris flow erupting is bound to increase substantially.