A strength model of interface between soil and cement grout influenced by the degree of saturation

Yan Liu , Ye Feng , Yuxin Zhao , Wen Zhang

Abstract

The soil-cement grout interfaces are commonly involved in a wide range of civil engineering, and their strength significantly influences the stability of the whole structure. This paper investigates the strength of the interface between unsaturated soil and cement grout. A series of direct shear experiments are conducted on the interface under different initial water contents. Based on the test results, the strength equation expressed in terms of the degree of saturation was proposed. The proposed expression does not include suction, thereby avoiding the need for its measurement or control. Furthermore, a constitutive model for the soil-grout interface is then established within the framework of the disturbed state concept. The critical state strength equation is adopted to represent the fully adjusted state, while an elastic model is taken as the relatively complete state. The shear modulus related to the degree of saturation is used in the elastic model. The model has a total of 8 parameters, including 4 strength parameters, 2 elastic modulus parameters, and 2 disturbance parameters. All these parameters can be predicted by direct shear tests. The model is validated against experimental data, and the corresponding model parameters are analyzed accordingly. Results show that the proposed model can satisfactorily reproduce the interface behavior. The proposed model requires only conventional direct shear tests, effectively simplifying experimental and computational procedures and shortening test duration.

Key Words

cement grout; degree of saturation; interface; strength model; unsaturated soil

Address

Yan Liu, Ye Feng — Key Laboratory of Urban Underground Engineering of Ministry of Education, Beijing Jiaotong University, Beijing 100044, China
Yuxin Zhao — Key Laboratory of Urban Underground Engineering of Ministry of Education, Beijing Jiaotong University, Beijing 100044, China; Institute of urban systems engineering, Beijing academy of science and technology, Beijing 100089, China
Wen Zhang — Key Laboratory of Urban Underground Engineering of Ministry of Education, Beijing Jiaotong University, Beijing 100044, China; Hohhot Electric Power Survey and Design Institute, Hohhot Power Supply Company, Hohhot, Inner Mongolia, 010090, China

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