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Abstract Field observation，theoretical analysis and in-situ tests and monitoring were carried out in order to tackle the problem of large deformation and roof caving of roadways with super-large cross-sections and soft and weak coal roofs. The reasons of the problem were found to be the weak supporting structure of the roof，the weak connections between the roof and the two side walls of the roadway，and the occurrence of large tensile stress in the middle span of the roof. It was therefore proposed that the cross section of roadway to be equally divided into two parts for excavation one after another with multiple supporting structure(MSS) to strengthen the roof and roof-sidewall connection and reduce the deformation of the roof. A total of 10 factors were found to be vital to evaluate the roof safety. The proposed method was successfully applied to the coal mine at Wujiagou.
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Received: 02 April 2013
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2014, Vol. 33 
