Support Mechanism And Application Of Wire-Shell Bolting Shotcrete Support In Soft-Weak Rock Roadway

The supporting of soft-weak rock roadway is the weak link in the coal mine roadway supporting, and the situation gets more and more serious with the depth of exploitation increased. In order to make the soft-weak rock roadway get validly supported, It is necessary to make the outer rock surface and the inner part strengthened at the same time. The wire-shell bolting shotcrete support is put forward exactly based on this idea.This paper makes a deep study of the technique of the wire-shell bolting shotcrete support in the soft rock roadway, and of the supporting theory, using a combined method of theory analysis, model experiment, numerical simulation and field application.The main contents and results obtained in this paper are as follows:(1) By systemically summarizing the theory of soft-weak rock tunnel and the mechanism of wire-shell bolting shotcrete support, this paper makes an abstraction of the related basic theories, and lays a theoretical foundation for the whole study in this paper.(2) Based on the similarity theory, similitude criteria of the surrounding and the structure of supporting is educed. Making a comparison model experimental study on the wire-shell bolting shotcrete support with backfilling or not. in soft-weak sock roadway, and getting the curve of surrounding rock deformation and loads, reaching on deformation failure rule of the surrounding rock, the paper offers a reasonable reference for the support designing.(3) The numerical simulation shows support with backfilling makes the loads distribute uniformly around the structure of wire-shell bolting shotcrete support, and support strength rise highly. Displacement variation behavior, stress distribution, plastic zone variation behavior and support system force conditions of roadway surrounding with different support parameters are studied in contrast, then accordingly rationality of the wire-shell bolting shotcrete support with backfilling is demonstrated. (4) According to the result of field monitor measuring, surrounding deformation behavior and support system force conditions are studied, and are compared with the results of model experiment and numerical simulation. The three are almost identical. It shows that the wire-shell bolting shotcrete support with backfilling can make full use of the carrying capacity of the support system and rock surrounding, can availably control the loose ring's expand and displacement, which is good for the stability of the roadway.