为有效解决极高水压下微裂隙狭小硐室安全掘进中突水淹井的施工难题，依托大瑞铁路高黎贡山隧道1#竖井井底车场硐室超前堵水施工，针对竖井极高水压（7.6 MPa），地层蒙脱石含量高、可注性差，井底排水能力有限，注浆堵水难度大、要求高等特点，在钻注设备选型配套和设备拆卸吊装、极高水压防突措施、超前堵水启动和结束标准制定等方面进行现场试验研究与应用，得出以下结论： 1）提出极高水压下微裂隙深大竖井井底车场超前堵水注浆“合理步距、封堵水流；由外到内、环环相扣；间隔跳孔、锁定水源；增加补孔、局部加强”的原则； 2）定制大功率窄体履带式液压钻机并配置无级变速超高压低流量双液泵，满足狭小空间钻机反复拆、吊快速安全施工； 3）采用溶液型的改性脲醛树脂，以2～3倍静水压力作为注浆终压，有效解决了地层可注性差的问题，达到了较好的堵水效果； 4)通过原位压水试验预测前方涌水量并结合井内实际抽排能力，明确“以堵为主、限量排放”的治水原则，利用钻孔压水试验计算渗透系数并以此来制定超前注浆启动标准，以达到注浆效果的渗透系数确定堵水结束标准； 5）确定注浆最优循环长度为25 m，综合施工效率达到最高。

When tunneling in a narrow chamber with microcracks and extremely high water pressure, water gushing or shaft flooding occurs. To address this problem, a case study is conducted on the chamber of the bottom car yard of inclined shaft No. 1 of the Gaoligongshan tunnel on the DaliRuili railway. The site conditions are complex and include water pressure as high as 7.6 MPa, large montmorillonite content, poor groutability, limited drainage capacity of the shaft bottom, difficult grouting and water plugging, and high construction requirements. Therefore, field tests are performed regarding selection and matching, equipment disassembly and hoisting, antioutburst measures for extremely high water pressure, and standards for starting and ending water plugging in advance. The following conclusions are obtained: (1) An advance water plugging and grouting scheme is proposed. This scheme includes rational step distance, water sealing, inside first and then outside, process connection, interval grouting, water source locking, increasing grouting holes, and local strengthening. (2) A highpower, narrowbody crawler hydraulic drill equipped with a stepless variablespeed ultrahighpressure, lowflow doubleliquid pump is customized for fast construction of repeated equipment disassembly and hoisting in narrow spaces. (3) The solutiontype modified ureaformaldehyde resin is adopted, with 23 times hydrostatic pressure as the final grouting pressure, improving the groutability of the formation and achieving a satisfactory water plugging effect. (4) The insitu water pressure test predicts water inflow in front, and based on the actual drainage capacity in the shaft, a scientific and reasonable water control principle of "plugging as the main and limited discharge" is determined. The permeability coefficient is calculated using the borehole water pressure test to determine the advance grouting starting standards, and the water plugging ending standard is determined based on the permeability coefficient when achieving a satisfactory grouting effect. (5) The optimal grouting cycle length is determined to be 25 m, which can achieve the highest comprehensive construction efficiency.