Study On Mechanical Characteristics And Failure Mechanism Of Cemented Soil-Rock Mixture

With the rapid development of China's economic construction and the increasing scale of engineering construction,disasters caused by loose soil-rock mixture have occurred from time to time,causing huge loss of life and property.Grouting cementation is one of the common techniques in practice to improve the integrity of soil-rock mixture.The basic theory and experimental study of cemented soil-rock mixture can provide scientific basis for disaster prevention and control of related projects.In this paper,the effects of cementation materials,water content,particle size,water-to-binder ratio,soil-binder ratio,stone-gel ratio and other factors are analyzed by means of laboratory tests,numerical simulation and on-site measurement.Systematic research has been carried out on the mechanism of damage.The main achievements are as follows:(1)Based on the physical and chemical properties of soil,rock and cementing materials,the cementation characteristics of cement and Geopolymer solid-rock mixture are analyzed.It is proposed that cemented solid-rock mixture can be regarded as a multiphase system composed of cemented soil,block stone and weak interface between cemented soil and block stone.(2)The experimental study on the mechanical properties of cemented soil-rock mixture was carried out,and the effects of cementation strength and moisture content on the mechanical properties of cemented soil-rock mixture were compared and analyzed.It is concluded that the change of mechanical properties of cemented soilrock mixture is the result of the comprehensive action of various factors on cemented soil,block stone and cemented interface.The mechanical properties are positively correlated with the cemented strength,and negatively correlated with the particle size of block stone,water-cement ratio,soil-cement ratio and stone-cement ratio.(3)A numerical model of particle flow in cemented soil-rock mixture is established.The effects of key parameters such as cementation strength,stone content and particle size on the mechanical properties and crack evolution of cemented soil-rock mixture are systematically studied,and the micromechanical mechanism of strength development and instability failure of cemented soil-rock mixture is revealed.(4)Established the significant evaluation model of influence factors,studied the sensitivity of tensile strength,compressive strength,cohesion and internal friction angle to water-cement ratio,soil-cement ratio,stone-cement ratio and particle size,obtained the main control parameters of mechanical properties of cemented soil-rock mixture,and put forward the design method of cementation reinforcement of soil-rock mixture.There are 58 papers,31 tables and 99 references.