Research On Application Technology And Key Theory Of Large Industrial Building Above Goaf

Coal is one of the main resources in China. A massive and wide range of goaf is formed in whole country after years of exploitation. With the high increase of national economy, the land resources are more precious than before. Meanwhile, as many exploitation enterprises have changed their development direction to satisfy the demand of continual development. Many industrial construction, civil construction and traffic engineering need to be constructed above old and new goaf . But the goaf may be activated ,and then the deformation which will harm the projects constructed here may be increased and speeded by the additional load on the goaf surface. There is still a lack of systemic study and project practice concerning above issue by far. Thus research on systemic control and engineering technology application about goaf is important and urgent.In this paper, the destructive rule of goaf and characteristic of earth's surface shift were introduced and investigated. The stability of goaf has been analyzed by the non-linear finite element method. Technology of foundation treatment for building constructed above large-scaled goaf is formed combining with practice.It is a new assignment to construct a great cement industrial construction above goaf. The main difficulty is that the structural load including static and dynamic is heavy, and the project is sensitive to sedimentation, which required that the asymmetric sedimentation is not more than 10mm/60m. Moreover, the condition of geology is complicated, the goaf that will be used as constructed land have existed for many years and the rocks covering the peak of goaf are soft rocks. At last, there is no experience that can be learned from, because the land used by the project does not agree with the stipulation promulgated by current relational technical standard. There is not precedent for constructing a 2500t/d large cement industrial construction above goaf in homeland, and there is also not concerning report published in overseas.Considering the characteristic of the land and the specialty property of the project,the following research has been carried out by this paper:1.Applied synthetically many new technique in domestic and overseas ,such as drilling, physical prospecting and field test etc, to evaluate scientifically the condition of goaf,the engineering characteristic of the coving peak rocks,the hollowed degree that piled up object collapsed in roof,and the stability of the goaf. 2. Optimized the treatment scheme of goaf, which is reinforced by grouting or half grouting in different district according to experiment. The foundation was reinforced by half grouting after the calculation based on a new calculation model of foundation. 3.To ensure the results of treatment, such experiment as grouting, pore-forming drilling and the rock core , pressing water , the elastic wave speed, the single axial compressive strength of the calculus body and the elastic modulus have been carried out in this project. Then, experimental results acquired by experiment of pressing water were suggested as the engineering index evaluated the processing result of goaf. A new style of CF grain form of admixture was used to reinforce goaf. To find proper mixture ratio suited to goaf, system researches about physical properties of the admixture of flash and cement, and the mechanical characteristic of the calculus body have been carried out. To master the rule of building sedimentation, the sedimentation of the building was observed during the stages of construction and application. Moreover, to provide scientific instruction for the safe operation of the production line, the process and amplitude of sedimentation was analyzed.This research combining engineering practice, such key technical puzzles as the detection, stability evaluation, treatment and quality monitor of goaf etc have been solved. These key technologies enabled the engineering to satisfy the requirement of design and the long-term stability. And the experiences about goaf reconnaissance and foundation treatment were accumulated to formed a kind of relatively maturity theory, which contribute well to the development and construction of building above goaf in the future.