Experimental Study On The Correlation Between The Residual Strength Parameters Of The Viscous Slip Soil And The Directional Clay Of Mineral

At present,China has become one of the countries which are damaged and threatened most seriously by geological disasters,such as landslide,etc.It becomes emergent and extremely important to prevent and bring the damage to treatment.The value of residual strength parameters of slip zone is the key in landslide stability evaluation and landslide control engineering design.it is especially important to obtain residual strength parameters quickly in landslide emergency treatment.However,it is urgent to solve the problem of how to obtain accurate residual strength parameters quickly and economically.The aim of this paper is to provide a new idea and method for obtaining accurate residual strength parameters,which has theoretical,scientific,and practical value for landslide pre-warning and stability evaluation,as well as emergent engineering designs.This study uses 25 groups of typical natural viscous slip soil of 5 kinds of landslides in different regions as the research object.Based on the constant pressure ring shear,X ray diffraction(XRD)on the soil,foundation liquid plastic limit test,and other tests,it studies the fundamental factors to the residual strength of slip soil-(the directional arrangement of mineral)the correlation of directional residualand parameters strength.The main conclusions are in th following:(1)Under the condition of large deformation,it is generally considered that the cohesion c is 0.In the evaluation of residual strength in engineering application,only residual angle of internal friction should be considered(2)Neither the plastic index nor the percentage of clay particles can be used as the estimation factors of the residual strength parameters of cohesive soils.when the plasticity index is less than 40(IP<40),there is no clear correspondence between the plasticity index and the residual strength parameters;when over 40(Ip?40),a certain correspondence exists;when the percentage is from 40%to 70%(40%<CF<70%),the effects of clay content on the residual strength parameters ?_r is not very significant;only when the clay content is less than 40%or greater than 70%,a negative correlation is showed between the percent of viscous slip soil clay and the residual strength parameters ?_r.(3)When smectite is rich in viscous slip soil,smectite content can be used as the parameter value of residual strength parameter ?_r.Oriented mineral smectite has a strong control effect on the residual strength parameters of clay.The friction strength between the smectite flake particles is low.Viscous slip soil with over 30%of smectite can reduce the residual strength of viscous slip soil.Significant correlation exists between them.When the percentage of smectite is less than 30%,no significant correlation exists.(4)The directional arrangement of all directional minerals is the root cause of the residual strength.The residual strength parameter ?_r of the viscous slip soil increases with the increase of the total amount of directional clay minerals.In the practice of landslide emergency prevention and controlling,the correlation equation between the residual strength parameter and the total quantity of oriented mineral can be fully applied to obtain the scientific and reasonable residual strength parameter index conviniently and economically.