Experimental development process of similar material of water resisting layer in physical model test

¹ Shandong University of Science and Technology, State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Provence and the Ministry of Science and Technology, Qingdao 266590, China.
² School of Energy and Mining Engineering, Xi’an University of Science and Technology, Xi’an 710054, China.
³ China Coal Technology and Engineering Group Shenyang Research Institute, Fushun 113122, China.
⁴ State Key Laboratory of Coal Safety Technology, Fushun 113122, China.

^* Corresponding author: chensj@sdust.edu.cn

Abstract

The stability evaluation of water resisting layer in the process of coal mining is the key to study the law of water and soil loss and prevent the loss of water resources. The development and proportioning of similar materials are the basis to study the stability of water resisting layer by physical simulation. A new type of similar material considering water characteristics was developed through orthogonal experiments. The similar material was composed of river sand, bentonite, silicone oil, vaseline, and water. Determine the best test development process. First of all, the proportion test scheme is designed based on the orthogonal test. Then, the influence of cement concentration, mass ratio of silicone oil to vaseline and other components on the density, uniaxial compressive strength, elastic model and Poisson’s ratio of similar materials was analyzed by range analysis. Finally, the multiple linear regression equation between the parameters and the composition of similar materials for water resisting layer is obtained, and the optimal composition ratio is further determined according to the relationship between the test influencing factors and the mechanical properties of similar materials. The results show that the selected raw materials and their proportioning method are feasible. The content of river sand plays a major role in controlling the density and Poisson’s ratio of similar materials. The mass ratio of aggregate to binder is the main factor affecting the uniaxial compressive strength and elastic modulus of similar materials, while the cementing concentration has the second largest influence on the density, uniaxial compressive strength, elastic modulus and Poisson’s ratio of similar materials. Determining the cementing concentration that matches the design of similar material model tests is critical to improving test accuracy and provides a reference for the preparation of similar materials for water resisting layer under different requirements during the development of similar materials.