In this paper, the Cosserat theory that has been incorporated into a three dimensional finite element code COSFLOW, is applied to analyze the development of bed separations in the layered overburden and grout injection into the bed separations. The mechanism of bed separation development during the longwall mining is investigated. A parametric study is carried out to investigate the effect of major factors including hard rock grade, panel height and panel weight on bed separation development. Based on the modeling, a conceptual model to describe the development process of bed separation is proposed. The effect of grout injecting into the bed separations on subsidence reduction is also studied and the conclusion agrees well with the common realization.
Increasingly, mine subsidence is becoming a major issue of community concern. Among the measures of subsidence control, a more effective and economical technology, namely Overburden Grout Injection Technology (OGIT), is recently developed in China and Australia by injecting waste material into the bed separations during longwall mining to achieve subsidence control. The OGIT is proposed for the subsidence control in West Cliff Colliery located at the Southern Coalfield of the Sydney Basin, Australia. The three-dimensional finite element code COSFLOW is applied to investigate in a detail the bed separation developing with longwall mining and the effect of grout injecting into the separations in order to guide the subsidence control design when using the OGIT in West Cliff Colliery longwall mining practice.
One of difficulties in super long tunnels’ construction is the construction ventilation to meet the requirement of normal construction environment and assure the workers’ health. Using traditional tunnelling ventilation is very difficult to meet the need of super long tunnel construction. As the energy assumption is high and it is very expensive. This paper investigated the simulation of tunnel construction ventilation with large power jet fans during the construction of Jinping Auxiliary Tunnels by using the computational fluid code FLUENT, the layout of jet fans in the tunnels is optimized. It is found that the best layout of the jet fan is aroud the transverse channel under the direction of airflow and jet fan should not be too far away from the transverse channel. The CO mainly distributes in the upper part of the tunnel when the jet fan is installed at a higher position, this layout of the jet fan is beneficial to construction of tunnels.
Through the analysis of ‘gap parameter’ and ground movement pattern in shield tunnel, this paper researched and corrected the model of ‘equivalent circle zone’ proposed by predecessors. The ‘equivalent circle zone’, which is a comprehensive reflection of shield gap, grouting filling and stratum perturbation, is considered to be unequal thickness in this paper. With the measured data of practical shield tunneling, the unknown parameters of corrected ‘equivalent circle model’ can be obtained by back analysis through numbering analysis. The back analysis of Shen Zhen line-5 is carried out to validate the rationality of the method proposed in this paper. Research shows that: the corrected model can reflect the feature and values of ground settlement more factually than the previous model and can offer a reference to predict ground deformation during shield tunneling.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.