煤矿斜井井筒过流砂层施工技术研究及应用

Study and application of construction technology for inclined shafts penetrating drift sand strata in coal mine

流砂层是矿井建设常遇见的不良地层,在含水或动力扰动下具有自流动性,施工不当会引起流砂向临空面流动充填开挖空间将井筒淹没或造成地表大面积塌陷。采用工程地质钻探与地面直流电法勘探技术,确定了流砂层的厚度与含水特征;根据斜井井筒穿越流砂层的垂深,将斜井井筒过流砂层技术方案进行分类研究,提出了斜井井筒过不同厚度流砂层的合理掘进技术;基于理论分析与数值计算,确定了斜井井筒支护结构承受的荷载,提出了斜井井筒过流砂层合理的井壁结构;为评价支护效果,对斜井井筒围岩变形、型钢支架受力、二衬接触应力、衬砌钢筋受力及渗水压力等进行了实时监测,监测结果表明:斜井井筒过流砂层的施工技术方案分类合理,保证了斜井井筒的掘进进度与施工安全;井壁结构安全可靠,保证了斜井井筒围岩与支护结构的稳定。

The drift sand stratum is a kind of common harmful stratum in mine construction. It is characterized by auto flow ability in water or under dynamic disturbance. Improper construction will cause the drift sand to flow to the free surface to fill the excavation space and get the shaft flooded or lead the ground to collapse. The water-holding condition and thickness of drift sand strata are determined by using engineering geological drilling and electrical prospecting technology. Based on the vertical depth of drift sand stratum, the constructing techniques for the inclined shaft penetrating the drift sand stratum are classified. A reasonable tunneling technology is presented for the inclined shaft penetrating the drift sand stratum with different thicknesses.Pressure ability of structure is calculated by means of both finite element method and analytical method. The reasonable structure of shaft lining is proposed. To evaluate the supporting effect, deformation, stress and permeability strength are monitored. The results show that the construction technology for the inclined shaft penetrating the drift sand stratum is reasonable, thus the tunneling progress and construction safety are ensured, and the structural safety and surrounding rock ability are guaranteed.