Abstract
The lithology of the roof of the mining roadway is compound and the thickness of each layer varies considerably, and it is disturbed by dynamic load all the year round. The above factors has caused a huge difference in the stability of the roadway surrounding rock. Taking the 11,020 lower tunnel of a mine in Henan Province as the engineering geological background, using on-site investigation, formula derivation, numerical simulation and other methods, the composite roof roadway model group was established to study the deflection evolution characteristics of the surrounding rock under dynamic load disturbance, and summarize the plastic zone of the surrounding rock of the roadway Deformation and evolution of roof surrounding rock to evaluate the stability of surrounding rock with different roof structures. The research results show that the change of the roof surrounding rock structure will also lead to the change of the center deflection of the roadway roof. Therefore, the center deflection of the surrounding rock of various roof composite structures is different, and the deflection is the most direct indicator of the stability of the surrounding rock. The center deflection (\(\omega_{0}\)) of the soft rock type is the largest, the center deflection (\(\omega_{0}\))of the upper soft and the lower hard type, and the soft and hard type is larger, and the soft and hard progressive type, thin, hard and thick soft type (\(\omega_{0}\)) is the smallest, and the dynamic load The relationship between the magnitude of deflection before and after the disturbance is consistent. By constructing a composite roof roadway numerical model group, using the plastic failure zone of the roadway as the evaluation standard, the surrounding rock stability is evaluated and divided, and then the cross-point field measurement method is used to verify the stability of the surrounding rock on the roof of different composite structures. And the development of composite roof roadway surrounding rock deformation and failure mechanism and numerical simulation method has important theoretical significance and practical value for the analysis and control of composite roof roadway surrounding rock stability.
Highlights
The total number of newly excavated roadways around the world is tens of thousands of meters long
The roof of roadways is often composed of surrounding rocks of different lithologies, and the roles of each rock layers in underground activities are different
The roof lithology mainly includes soft mudstone, Based on the columnar and combined forms of medium-strength sandy mudstone and a small amount of boreholes(Jiang 2014) obtained from the exploration of hard sandstone.The roof lithology and thickness of the the rock strata structure of the roadway and the large same roadway vary greatly, and there are many types of amount of field measurement data of the composite roof composite structures, the roof pressure is high, and layered roof structure by predecessors, the composite various dynamic events frequently occur during the roof structure is divided into five typical structure types: mining period
Summary
The total number of newly excavated roadways around the world is tens of thousands of meters long. All of the above working faces have the characteristics of large mining depth, composite structure of roadway roof, and frequent dynamic events, which factors have had a huge impact on the development and utilization of coal resources. The roof lithology mainly includes soft mudstone, Based on the columnar and combined forms of medium-strength sandy mudstone and a small amount of boreholes(Jiang 2014) obtained from the exploration of hard sandstone.The roof lithology and thickness of the the rock strata structure of the roadway and the large same roadway vary greatly, and there are many types of amount of field measurement data of the composite roof composite structures, the roof pressure is high, and layered roof structure by predecessors, the composite various dynamic events frequently occur during the roof structure is divided into five typical structure types: mining period.
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