冻结立井地层力学特征与竖井开挖方案研究

    Research on mechanical characteristics of frozen strata and excavation schemes for vertical shafts

    • 摘要: 针对复杂含水地层立井施工难题,现已围绕冻结条件下地层力学特征与竖井开挖方案展开了系统研究。选取典型岩样在−5 ℃、−10 ℃、−15 ℃条件下开展直剪、单轴压缩与热学参数测试,建立岩体强度-变形-热学参数的温度响应规律。研究结果表明:中粒砂岩单轴抗压强度由13.48 MPa升至32.28~40.48 MPa(−5~−15 ℃),承载能力显著增强。多数砂岩导热系数随温度降低小幅上升(<10%),比热容略降且总体接近。在非冻结含水段,涌水会导致泥岩强度降至约3.53 MPa,需要据此调整撑靴参数与施工工序组织。根据测试结果与工程约束,提出“冻结改性与机械化掘进(干式排渣)”的协同设计思路。在系统方案中还可预置双排渣模式以降低段落切换成本,同时确保冻结壁满足竖井掘进机撑靴荷载要求。相关研究成果可为深部立井安全、高效施工提供参数依据和方法支撑。

       

      Abstract: The mechanical characteristics of strata and shaft excavation schemes are systematically investigated under frozen conditions to address vertical shaft construction in complex aquifers. Representative lithologies are tested at −5℃, −10℃, −15 ℃ by direct shear, uniaxial compression, and thermal-property measurements to establish the temperature-dependent responses of strength, deformation, and thermal parameters. Results show that the uniaxial compressive strength of medium-grained sandstone increases from 13.48 MPa at room temperature to 32.28-40.48 MPa at −5 ℃ to −15 ℃, markedly enhancing load-bearing capacity. For most sandstones, thermal conductivity rises slightly (<10%) as temperature decreases, whereas specific heat capacity declines marginally and remains comparable in magnitude. In unfrozen water-bearing sections, inflow reduces mudstone strength to about 3.53 MPa, indicating the need to adjust gripper-shoe settings and process organization. Based on the test results and engineering constraints, a coordinated scheme of “freezing modification and mechanized shaft sinking (dry muck removal in frozen sections)” is proposed. The systematic scheme incorporates a dual muck removal mode to reduce transition costs between sections, while ensuring the frozen wall satisfies the gripper load requirements of the shaft boring machine. These research findings provide the necessary technical parameters and methodological support for the safe and efficient construction of deep vertical shafts.

       

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