Abstract
In order to study the mechanism of excavation and supporting process of equivalent circular roadway, the model of soft roadway was established firstly. The elastoplastic solutions in excavation process were deduced based on Drucker‐Prager strength criterion. Then, the elastoplastic solution under supporting condition was obtained based on homogenization method under the condition of rockbolts and liner supporting. Lastly, an example was analyzed to study the effect of different factors such as “space effect,” supporting opportunity, stresses, surrounding displacement, and the radius of plastic zone. Based on theoretical research case, the change rules of considering the “space effect” and the supporting opportunity when calculating the subarea of the roadway were discussed, the control of interval distance of rockbolts on the displacement of surrounding rock mainly reflecting in the plastic residual zone and the “space effect” in excavation, and the supporting time to control the displacement of surrounding rock not being ignored are revealed. The results can provide an important theoretical basis for the stability evaluation and quantitative support design of roadway surrounding rock. Therefore, the “space effect” and the supporting time to control the displacement and stresses of surrounding rock can not being ignored in underground engineering.
Highlights
Coal has long been the main energy source in China [1, 2]
In view of the exhaustion of shallow resources in recent years, the resource exploitation and space development gradually have been transferred to the deep earth [3, 4]. e complex mechanical environment of “three heights and one disturbance” in deep coal and rock body leads to many problems and challenges in deep mining [5, 6]. ey lead to the strength degradation of rock mass, which affects the stability of underground engineering [7]. e development and establishment of new theories and methods are the theoretical basis of surrounding rock control in deep underground engineering, which is of great significance to guide the surrounding rock control technology and engineering practice of kilometer deep roadway
In this paper, based on D-P strength criterion and the noncorrelation flow rule, an equivalent circular roadway solution method is proposed. e stress and deformation of surrounding rock of underground roadways are obtained by the elastoplastic theory. en, the failure mechanism of roadway with soft rock is analyzed
Summary
Coal has long been the main energy source in China [1, 2]. In view of the exhaustion of shallow resources in recent years, the resource exploitation and space development gradually have been transferred to the deep earth [3, 4]. e complex mechanical environment of “three heights and one disturbance” in deep coal and rock body leads to many problems and challenges in deep mining [5, 6]. ey lead to the strength degradation of rock mass, which affects the stability of underground engineering [7]. e development and establishment of new theories and methods are the theoretical basis of surrounding rock control in deep underground engineering, which is of great significance to guide the surrounding rock control technology and engineering practice of kilometer deep roadway. E stress and plastic zone distribution state of surrounding rock of deep roadway is an important basis for evaluating the stability of surrounding rock and the reliability of quantitative support design. Advances in Civil Engineering criteria are employed as associated and nonassociated potential flow laws On this basis, the surrounding rock stress and deformation distribution is analyzed by ideal elastoplastic and elasto-brittle-plastic mechanical models. Due to the traditional elastic-plastic analysis of the roadway based on two-dimensional plane strain, considering the “space effect” can analyze the stress, displacement, and other analytical changes caused by threedimensional excavation of the roadway Both theory and practice have shown that, after roadway excavation, most of the rock mass is still in the state of three directions. E results can provide important theoretical basis for the stability evaluation and support design of surrounding rock
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