Anlysis Of Clamber-top Ground Arch Morphology And Surface Subsidence Patterns During Underground Clamber Excavating

Stratum settlement and ground arch are often caused by the excavation of underground engineering, especially in the process of the development and utilization of urban underground space. And surface buildings are damaged at different degree. It is of important theoretical value and engineering guiding significance to underground construction works with a high-speed development in our country to understand and grasp clamber-top ground arch morphology and surface subsidence patterns during underground clamber excavation. Combined with laboratory similar material model test, theoretical analysis and numerical experiments, the clamber-top ground arch three-dimension morphology and surface subsidence patterns of underground clamber excavation were studied in this paper. The main research results are as follows:(1) Based on similar material model test, data of three-dimensional laser scanning image for clamber-top ground arch morphology were analyzed under different excavation sequences and different thickness of overlying strata. The conclusions are obtained in this paper:the range and rise of ground arch increase with the increasing of excavation area while they have nothing to do with the thickness of overlying strata.(2) The similar material model test is supplemented and perfected by using finite difference software FLAC3D. The clamber-top ground arch morphology of excavation is showed as an arcuation and the surface ultimate settlement is maximal in the center of excavation face in the numerical simulation analysis. The evolution law of overlying strata settlement is rebuilt by equivalent hyper-surface, and it is in accordance with similar test. The following conclusions are obtained from the analysis of final settlement for nodes. With the increasing thickness of overlying strata, the maximal surface settlement decreases while the influence scope of settlement increases.(3) A simple three-dimensional laser scanning device for clamber-top ground arch morphology during underground engineering excavation is developed to rapidly establish model of three-dimensional space morphology. The space morphology is 3-dimensional laser scanned and engineering deformation is monitored for clamber, roadway, square-cavity, mined-out area and so on by this device under the situation of non-contacting and non-turbulent the engineering. By this device, the data density is optimized and decreased. What’s more, this device is characterized by simple operation, lower price and convenient carrying.