of PhD Thesis It discovers that the most fundamental problem in existed roadway support theories is not to make a distinction between the support actions in effect in different time.It is put forwards that the action of roadway support should be divided into restraining action and stabilizing action.Based on the above acknowledge,the subject of roadway support,stability conditions of surrounding rocks and interaction mechanism between support and surrounding rocks are reestablished,and the related formulas to calculate forces of restraining and stabilizing actions of support are built up by means of limit analysis method.Using the formulas,the main problems of roadway support theory,including relations between restraining action and stabilizing action,influences of second principal stress,peak strength,residual strength,dilatation,coefficient of internal friction,coefficient of plastic strain-softening,and Poisson ratio on support are calculated and discussed in detail.Throuth the above research,the basic structure of restraining and stabilizing action theory of roadway support is formed finallyand the following conclusions are reached. (1)The action of support before the flow and plastic strain softening zones of surrounding rocks of roadway formed,called restraining action,is mainly to control the size of the two zones. The action of suppor after the major part of two zones formed,called stabilizing action,is mainly to change the relationship between rock strength and stress and make unstable state rock reach stable condition again. (2)The subject of support is surrounding rocks in flow zone,plastic zone,and part of elastic zone which is adjacent to plastic zone.The related support force can be determined according to the common boundary of plastic zone and elastic zone to reach stable conditions. (3)Stabilizing support force is strongly in fluenced by the time effects of friction strength,cementation strength and second principal stress.It is of great significance to study them separatedly. (4) The stability of roadway surrounding rocks under elasic state,plastic softening state and flow state is dependent of the relationship among the strength and stress of rocks and allowable deformation of support structure. (5) In given condition,the appropriate support type depends on relevant rock strength.When rock compression strength is less than two times of original rock stress,the stabilizing type support should be choosed.In this way,the initial support force should be as small as possible under the condition effectively to prevent roof collapse.Otherwise,restraining type support shoule be used. (6) The formulas of roadway support force are derived to consider plastic strainsoftening and dilatation properties of rocks,and the influences of second principal stress.The formulas are used for practical case and a comprehensive repairing program using back packing and grouthing technology is developed. comprehensive repairing program using back packing and grouting technology is developed. of PhD Thesis It discovers that the most fundamental problem in existed roadway support theories is not to make distinction between the support actions in effect in different time. It is put forwards that the action of roadway support should be divided into restraining action and stabilizing action .Based on the above acknowledge, the subject of roadway support, stability conditions of surrounding rocks and interaction mechanism between support and surrounding rocks are reestablished, and the related formulas to calculate forces of restraining and stabilizing actions of support are built up by means of limit analysis method. Using the formulas, the main problems of roadway support theory, including relations between restraining action and stabilizing action, influences of second principal stress, peak strength, residual strength, dilatation, coefficient of internal friction, coefficient of plastic strain-softening, and Poisson ratio on support are calculated and discussed in detail.Throuth the ab ove research, the basic structure of restraining and stabilizing action theory of roadway support is formed finally and the following conclusions are reached. (1) The action of support before the flow and plastic strain softening zones of surrounding rocks of roadway formed, called restraining action, is mainly to control the size of the two zones. The action of suppor after the major part of two zones formed, called stabilizing action, is mainly to change the relationship between rock strength and stress and make unstable state rock reach stable condition again. 2) The subject of support is surrounding rocks in flow zone, plastic zone, and part of elastic zone which is adjacent to plastic zone. The related support force can be determined according to the common boundary of plastic zone and elastic zone to reach stable conditions . (3) Stabilizing support force is strongly in fluenced by the time effects of friction strength, cementation strength and second principal stress. It is great significance to study them separatedly. (4) The stability of roadway surrounding rocks under elasic state, plastic softening state and flow state is dependent of the relationship among the strength and stress of rocks and allowable deformation of support structure. , the appropriate support type depends on relevant rock strength .When rock compression strength is less than two times of original rock stress, the stabilization type support should be choosed.In this way, the initial support force should be as small as possible under the condition effectively to prevent roof collapse. Otherwise, restraining type support shoule be used. (6) The formulas of roadway support force are derived to consider plastic strain of dilatation properties of rocks, and the influences of second principal stress. The formulas are used for practical case and a comprehensive repairing program using back packing and grouthing technology is developed. comprehensive repairing program using back packi ng and grouting technology is developed.