Experimental Study On Debris Flow Impact Liquefaction Mechanism Of Easily Liquefied Layer

The main research contents of this paper are to obtain the velocity and distance of the liquefied and then slipped by the impact of different particles on the bulk body.The changes of the pore water pressure and the vibration signal and the external form in the accumulation body are analyzed to obtain the influence of the sliding speed and Distance factor,analysis of the impact of liquefaction mechanism.The test was set up as a large slope slot where the debris flow was placed and a small pitch slot where the steady-state deposit was placed,both of which were connected by a relatively curved groove.The debris flow uses two distinct materials: a diameter of 15 mm,the surface is smooth,the shape is extremely close to the circular deformation of the ball and the diameter of 2cm-5cm,rough surface,irregular shape of the stone.Both materials are divided into 15 kg,20kg,25 kg three weight.During the test the simulation of sudden,rapid debris flow at the corners of the impact into the accumulation of body.Through the LabVIEW program synchronization acquisition of the laying of the pore water pressure sensor,micro-vibration sensor in the test process of real-time data to ensure data reliability.The high-speed camera is used to monitor the motion characteristics of the stack at the corresponding time.And then compare the different types of debris flow and different mass of debris flow and the same quality of different types of debris flow test data,a profound understanding of debris flow impact liquefaction layer liquefaction mechanism.Based on the results of this study,the mechanism and migration of liquefaction of liquefied liquefaction layer are analyzed.The results show that:1.The impact of liquefaction mechanism is the accumulation of debris flow by the impact of intense impact,the volume in a very short period of time to be compressed,the particles vibrate,destroy the original soil between the state and the state of the joint.At this point,the original by the soil through its contact point of the stress(effective stress),it is necessary to pass to the pores of the water to bear,causing a sudden increase in pore water pressure,the effective stress suddenly reduced,the shear strength of the local Or all loss,that is,varying degrees of deformation or complete liquefaction.Soil in the liquefaction process,when the excess pore water pressure dissipation,liquefied soil will restore the solid characteristics.2.Sudden,high-speed debris flow on the accumulation of the body,especially its trailing edge has a denudation.The greater the mass of the debris flow,the stronger the erosion.Different types of debris flow erosion is not the same,there are strong and weak.Smooth,regular debris flow is stronger than rough,irregular debris flow.Smooth,regular debris flow leaving the erosion marks more intensive,the impact of the formation of the impact of the deeper surface,the impact of the formation of the body more holistic.3.The change of pore water pressure after the impact of the debris flow is related to the quality of the debris flow.The greater the mass of the debris flow,the faster the pore water pressure rises,the greater the maximum reaching,and the longer the liquefaction.After the pile is subjected to impact,the pore pressure of the leading edge begins to rise earlier than the trailing edge.4.The change of pore water pressure after the impact of the debris flow is related to the type of debris flow.Smooth,regular,dense debris flow is more rough than irregular,irregular debris flow is easier to make pore water pressure rise,and rise to reach the maximum greater.As the smooth,regular debris flow and the bulk of the contact surface is larger and more concentrated,so the earth particles can shake,pore water pressure rise,the effective stress is reduced.5.The same mass of debris flow,smooth,regular debris flow impact liquefaction produces more energy,soil particles move more frequently,the higher the pore water pressure rises.6.The greater the mass of debris flow,the faster the accumulation of body slippage,the greater the acceleration,the longer the migration time,the longer the distance from the slide.Smooth,regular debris flow than rough,irregular debris flow on the impact of the accumulation of a strong,faster speed,the distance farther.