深厚含水基岩区立井外壁冻结压力的实测与分析

摘要

In order to thoroughly investigate the load of outer shaft lining in deep aqueous bed rock area,in-situ measurements on freezing pressure of outer shaft lining were carried out in bed rock in Hujierte coalfield in Chinese Erdos.The in-situ measurement results reveal that the process of freezing pressure can be described by 4 periods：dramatic increase period,slow increase period,rapid increase period and gradual decrease period.The freezing pressure is mainly affected by rock moisture content and rock strength,but the rocks buried deep H affects little.The freezing pressure reaches 76.4%~89.8% of the maximum freezing pressure Pmax at 10~15 days after concrete pouring.Therefore,it is recommended using 7 days concrete strength index to guarantee the safety of outer shaft lining during the early period.The freezing pressure reaches the maximum value Pmax at 80~100 days after concrete pouring,the measured value of Pmax is 1.08~1.74 MPa.Pmax is much smaller than hydrostatic pressure P0 and the maximum freezing pressure Pω in deep alluvium.%为明确我国西部深厚含水基岩区立井外壁的载荷,在鄂尔多斯市呼吉尔特矿区开展了基岩冻结压力的现场实测研究。结果表明：凿井期基岩冻结压力的变化规律可分为急剧增长、缓慢增长、快速增长、逐步减小4个阶段;基岩冻结压力主要受原岩富水条件、强度等因素的影响,与岩层埋深H关系不大;基岩冻结压力在混凝土浇注后的10～15 d即达到冻结压力最大值Pmax的76.4%～89.8%,建议采用7 d混凝土强度指标来保证外壁早期质量;基岩冻结压力在混凝土浇注后的80～100 d增长至最大值Pmax,Pmax实测值仅为1.08～1.74 MPa,远小于按岩层埋深H换算的静水压力值P0,更远小于特厚冲积表土中的冻结压力上限值Pω。