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孔隙型含水基岩中荷载的合理取值是科学设计井壁的关键。现行荷载计算方法按井壁全外表面承担全部静水压力计算,随深度增加,围岩压力和地下水静水压力增大,井壁厚度急剧增加。为掌握孔隙含水岩层井壁真实的荷载情况,解决设计难题,在内蒙古鄂尔多斯某煤矿开展了井壁实测研究。实测数据表明:地下水静水压力对井壁的影响明显小于其作用于井壁全部外表面时的值,说明现行荷载计算方法偏于保守。分析认为:不同的地质条件下降低井壁荷载的方法并不相同,当围岩压力相对地下水静水压力较大时,增大衬砌与围岩接触面孔隙率可降低总荷载,当围岩压力相对地下水静水压力较小时,降低接触面孔隙率可使总荷载值减小,当二者相等时,总荷载值不受接触面孔隙率影响。基于上述分析,在深部含水岩层中采取的提高井壁与围岩接触质量的施工措施显著地降低了地下水静水压力的影响。
The reasonable value of loading in pore-type water-bearing bedrock is the key to scientific design of wellbore. The current load calculation method is based on the assumption that the entire external surface of the wellbore is responsible for calculating the hydrostatic pressure. As the depth increases, the surrounding rock pressure and the hydrostatic pressure of the groundwater increase, and the thickness of the wellbore increases sharply. In order to grasp the real load condition of the well wall of the aquifer with pore water and solve the design problem, a borehole measurement study was carried out in a coal mine in Ordos, Inner Mongolia. The measured data show that the effect of hydrostatic pressure of groundwater on the well wall is obviously less than the value of the hydrostatic pressure acting on the entire outer surface of the well wall, indicating that the current load calculation method is somewhat conservative. The analysis shows that the method of reducing the wall load under different geological conditions is not the same. When the surrounding rock pressure is relatively larger than the hydrostatic pressure of groundwater, increasing the porosity at the contact surface between the lining and the surrounding rock reduces the total load. When the surrounding rock pressure is relatively When the hydrostatic pressure of groundwater is small, reducing the porosity of the contact surface can reduce the total load. When the two are equal, the total load is not affected by the porosity of the interface. Based on the above analysis, the construction measures taken to improve the contact quality between the shaft wall and the surrounding rock in the deep aquifer significantly reduce the hydrostatic pressure of the groundwater.