Study on non-uniform stress characteristics of steel plate-reinforced concrete drilling shaft wall in Inner Mongolia and Shaanxi mining area
Taking the eastern air shaft of a mining area in Inner Mongolia and Shaanxi as the engineer-ing background,the stress form of the shaft wall under horizontal in-situ stress was derived by using the two-way unequal pressure model,and the calculation formula of non-uniformity coefficient k was obtained.The range of non-uniformity coefficient of strata in Inner Mongolia and Shaanxi mining area was 0.06~0.20,and the dangerous section of full depth of shaft was determined.The ANSYS soft-ware is used to simulate the stress of the shaft wall under non-uniform load conditions.The results show that the circumferential stress of the outer edge of the shaft wall concrete is the control stress,and the stress of the shaft wall is non-uniformly distributed.The degree of non-uniformity at the 90° position is greater than that at the 0°position.The 90°position with smaller external load is pulled,while the 0°position with larger external load is compressed.The non-uniform loading of the two cross-section models was carried out by using the shaft wall test bench.The results show that the non-uniform load has a very obvious influence on the stress of the drilling shaft wall.When k=0.15,the peak stress of model 1 is only 23.1%~33.3%of that under uniform load.When k=0.2,the peak stress of model 1 and model 2 is about 20%of that under uniform load,and the failure mode is that the concrete is first damaged by tension,and then the steel bar and steel plate yield.The results show that the inner steel plate-reinforced concrete drilling shaft wall is more sensitive to non-uniform load.The influence of non-uniform coefficient should be considered when using drilling method in In-ner Mongolia and Shaanxi mining area,and it is necessary to pay attention to the stress at the position where the load outside the shaft wall is small in the design stage of the shaft wall.
inner steel plate-reinforced concrete drilling shaft wallInner Mongolia and Shaanxi mining areanon-uniform loadforce characteristicsmodel test