富水砂层斜井明挖段三维冻结温度场时空演化规律研究  

Spatiotemporal evolution of three-dimensional freezing temperature field in open-cut section of inclined shaft in water-rich sand layer

作　　者：荣隽锋 王彬 梁沈伟 RONG Junfeng;WANG Bin;LIANG Shenwei(School of Civil Engineering,University of New South Wales,Sydney 2052,Australia;Engineering Research Center of Underground Mine Construction,Ministry of Education,Anhui University of Science and Technology,Huainan 232001,China)

机构地区：[1]新南威尔士大学土木工程学院,澳大利亚悉尼2052 [2]安徽理工大学矿山地下工程教育部工程研究中心,安徽淮南232001

出　　处：《煤炭工程》2024年第8期204-212,共9页Coal Engineering

基　　金：国家自然科学基金项目(51878005);矿山地下工程教育部工程研究中心开放基金项目(JYBGCZX2022103)。

摘　　要：为解决冻结斜井明挖段施工过程中,斜井冻结温度场难以准确预测导致开挖时间及速度无法确定的工程难题,以升富煤矿冻结斜井明挖段为研究对象,基于实测地层特性及冻结孔布置参数,采用COMSOL Multiphysics有限元软件,构建三维冻结温度场数值计算模型,对冻结斜井明挖段施工期间温度场的时空演化规律进行数值计算预测分析。计算结果表明:在相同冻结时间条件下,细砂层冻结壁平均温度比中砂层低0.28~2.39℃,细砂层冻结壁有效厚度比中砂层厚0.36~0.59 m。在持续冻结88 d后,明挖段冻结壁平均温度低于-12℃,且不同层位的侧帮冻结壁厚度均能达到4 m以上,底板处的冻结壁厚度均达到5 m以上,满足设计开挖需求。在开挖期间,井帮位置暴露的土体存在“热流侵蚀”现象,但在快速开挖施工的条件下,冻结壁的有效厚度并未减小且冻结壁平均温度仍处于-10℃以下,因此开挖过程中不会发生大范围的冻结壁“软化”现象。基于预测结果,制定了现场开挖方案,由现场实测数据可知,在开挖过程中测点及井帮温度出现轻微波动,但整体温度发展趋势较为稳定,表明施工期间冻结壁是安全稳定的。研究成果可为斜井冻结法凿井的安全施工及优化设计提供参考。In order to solve the engineering problem that the excavation time and speed cannot be determined due to the difficulty of accurately predicting the freezing temperature field in the open-cut section of freezing inclined shaft during construction,we took the open-cut section of frozen inclined shaft in Shengfu Coal Mine as the research object,based on the field measured formation characteristics and freezing hole layout parameters,constructed the three-dimensional numerical calculation model of freezing temperature field by using COMSOL Multiphysics finite element software,and analyzed the temporal and spatial evolution of temperature field during open-cut section of freezing inclined shaft with numerical calculation.The results showed that the average freezing temperature of fine sand layer was 0.28~2.39℃lower than that of middle sand layer,and the effective freezing thickness of fine sand layer was 0.36~0.59 m thicker than that of middle sand layer.After continuous freezing for 88 days,the average temperature of the frozen wall in the open-cut section was lower than-12℃,and the side frozen walls at different levels were thicker than 4 m,and the frozen wall at the bottom was thicker than 5 m,which met the design excavation requirements.During the excavation,the exposed soil mass at the well wall had the phenomenon of“heat flow erosion”,but under the conditions of rapid excavation construction,the effective thickness of the frozen wall did not decrease and the average temperature of the frozen wall was still below-10℃,so the phenomenon of“softening”of the frozen wall did not occur in a wide range during the excavation.Based on the predicted results,we proposed a site excavation plan.According to the field measured data,the temperature of the measuring point and well wall fluctuated slightly during the excavation process,but the overall temperature development trend was relatively stable,indicating that the frozen wall was safe and stable during construction.This study can provide reference for safe

关 键 词：人工地层冻结法 斜井 明挖段 冻结温度场 三维数值模型 

分 类 号：TD265[矿业工程—矿井建设]