Research On Resisting Theory And Strengthening Technology For Building On Mining Cave-In Areas

As all well known, the coal is one of the main energy sources. There are a lot of coal-mines all around of our country. Above these coal-mines, there are a lot of towns,factories and many kinds of natural villages. With the development of our economic, more and more coal is needed and mined. As a result, many constructions are on the mining cave-in areas. It is reported that the amount of coal under constructions,water and railways is about 13.79 billion tons. Out of these coal, the quantity of coal under constructions is about 8.76 billion tons(about 63.5 percent). It infects the living conditions of 600 thousands people.How to design resisting mining constructions that is reasonable in structure,and how to detect,estimate and strengthening existed constructions effectively,is a theoretical and technical problem that is not solved in construction protect in mining cave-in areas,up to now.Therefore, the following research works have been done:1. The influence of mining to the construction and the deformations of the surface of the mining cave-in area, as well as the deformations of the buildings and its foundations are analyzed.2. Many similitude materials simulating overburden layer and movement of overburden layer causing by underground mining are studied.3. With the theories of structural mechanic, mining settlement, soil mechanic and material mechanic, the common action between superstructure soil and foundation above mining cave-in area are studied and the mechanic model of this common action are made up. Using this model, the movement rule of foundation, internal force, subgrade reaction are studied.4. The additional acting force of building infected by mining has been studied and the assumption of the calculation to this force has been put forward. Also, the protecting methods to the building and the design methods to the building using the deformation stripe bases have been studied.5. The design theory to the buildings using "moving and rise-fall point foundation" in sink mining areas has been put forward, including design concepts, establishment of the formula for additional function,choice of constructional material, as well as the parameters to the moving and rise-fall point foundation. Through above works, the performances and load capacity of the structures have been improved.6. The theory of "conception strengthening" for the existing structures in the mining cave-in area,basical principle,structural strengthening procedures as well as evaluation methods to structures has been put forward.The research results have been used in an actual example.