Experimental Study On The Self-healing Of Red-bed Landslide Soil

The occurrence of landslides will pose a serious threat to people's lives and property.The occurrence and development of soil landslides is a progressive and gradual failure process.Soil landslides often slide more than once.After the first slide stops,it will enter a resting period.When rainfall or other factors induce,the landslide will slide again and cause disasters.The re-sliding of the landslide cannot be ignored and will cause more serious consequences.In landslide stability analysis and design calculations,the residual strength value of sliding zone soil is often selected.However,many studies have found that the selfhealing phenomenon of sliding zone soil occurs during the dormant phase,which is manifested by the increase in shear strength,which can be used for landslide treatment providing new ideas,so to clarify the internal mechanism of the strength recovery of the sliding surface,and to discover the law of self-healing will have great significance for engineering construction.Therefore,we selected a typical red-bed landslide in the Sichuan Basin-Xiejiawan landslide as the main body of the study.Based on detailed field surveys and on-site sampling,we conducted a large number of laboratory tests on the soil of the typical red-bed landslide.A detailed study of the healing effect is carried out,and a reference value of recovery is given through relevant test data to optimize the value of the safety factor.The main research results are as follows:(1)Both saturated and natural water content soils show obvious self-healing phenomenon.(2)Through the SHS experiments,it is found that as the normal stress increases,the shear strength of the soil shear surface also increases,but the recovery strength is limited.The normal stress plays a decisive role in the residual strength of the soil.As the holding time increases,the recovery intensity also increases,and is positively correlated with the holding time in a logarithmic coordinate system.After that,the number of filter papers was controlled to simulate the self-healing of the soil shear surface under different drainage conditions,and it was concluded that the better the drainage conditions,the more obvious the healing effect.(3)Through the ultrasonic experiments,it is found that as the holding time increases,the wave velocity difference measured before and after becomes larger,the sound wave propagation time becomes smaller,the peak duration of the waveform graph increases,and the energy attenuation becomes weaker.It shows that the soil sample is more complete and homogeneous after holding.(4)Through the SEM test on the shear surface of the soil after holding for different time,it is found that as the holding time increases,the soil particle structure of the shear surface becomes denser and the structure is continuously adjusted.It proves that there is structural restoration of the soil during the retention period.