【作者】 张驰；

【导师】 杨维好； 黄家会；

【作者基本信息】 中国矿业大学 ， 岩土工程， 2012， 博士

【摘要】 西部深厚富水岩层中，如何防止井壁在孔(裂)隙水压作用下与围岩相互剥离，避免100%井壁外表面受100%地下水静水压作用，事前如何预防井壁渗漏水通道的产生，事后如何封堵已经出现的渗漏水通道，是新型单层冻结井壁施工过程中急待研究并解决的关键技术与工艺！论文首先采用数值计算的研究方法，讨论了因掘砌施工导致的径向相互作用力fa的变化规律，计算结果表明：1) fa可表示为井筒埋深H的函数(fa=KfH)；2)冻结壁内缘径向卸载率η的常见值为0.403~0.911。基于轴对称平面应变模型，对新型单层冻结井壁进行应力分析，得到了凿井期井壁的应力与位移解析解。通过对总径向相互作用力f x变化规律的研究，提出了避免冻结壁解冻后井壁、基岩界面相互剥离的技术措施。针对新型单层冻结井壁可能存在的3个漏水通道，论文首先阐述了凿井期井壁裂纹(缝)产生的机理。尔后，综合采用数值计算与现场实测的研究方法，详细讨论了基岩段新型单层冻结井壁防冻害、防裂以及接茬注浆等关键技术，研究成果表明：1)当冻结管至井帮距离Df≥3m、井帮温度tb≥-5℃时，可确保井壁全断面正温养护时间≥26.7d；2)当混凝土后期趋于稳定的膨胀应变t不小于300μ，28d膨胀应变不小于50%(即150μ)时，可避免井壁产生环向、竖向温度裂纹(缝)；3)竖筋预紧力设计值可取为20kN，预紧工序应在混凝土浇筑至施工段高1/2之前完成；4)径向相互作用力fa对抑制井壁温度拉应力，效果较为显著；5)建议采用“下行式集中注浆”的方法进行接茬预注浆，注浆压力宜取为1倍静水压；6)若接茬持续3min不渗漏且注浆压力不下降，可认为注浆效果良好。以鄂尔多斯市呼吉尔特矿区葫芦素副立井为工程背景开展实测研究，实测成果表明：1)基岩冻结压力主要受原岩富水条件、强度等因素影响，与井筒埋深H无直接关系；2)基岩冻结压力极值Pmax仅约1.08~1.74MPa，远小于按实测井筒埋深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；3)凿井期竖筋、环筋应力的绝对值最大不超过70.8MPa和101.0MPa，仅接近井壁配筋HRB335强度设计值300MPa的1/3，故新型单层井壁配筋于凿井期具有足够的安全储备；4)实测层位F1~F3混凝土压应变极值均出现在井壁环向，且仅达到各层位混凝土极限压应变估算值max的25.7%、19.2%和19.0%，故凿井期新型单层井壁的混凝土压应变亦处于安全范围。最后，论文对基岩段新型单层冻结井壁的关键施工技术与工艺进行了总结，研究成果可为现场技术人员提供参考，对新型单层井壁的后续应用具有重要参考价值。更多还原

【Abstract】 In deep water-rich bedrock in West China, how should we do to prevent pore water pressurefrom separating shaft lining from surrounding rock when frozen wall thawing, how to avoid totalhydrostatic pressure on whole outer surf_ace of the shaft lining, what measures should we take toprevent leaking cracks in shaft lining in advance and deal with them through grouting technologyafterwards, the key technologies to solve these problems have become an urgent task in theconstruction of the new monolayer freezing shaft lining.In this paper, the variation of the radial interaction force f_acaused by shaft lining excavationis firstly discussed through numerical analysis. The results show that:1) f_acan be represented asa function of shaft depth H (f_a=K_fH);2) The common value of radial unloading rate η of frozenwall inner edge is0.403~0.911.Based on axisymmetrical plane strain model, stress and displacement analytical solution ofthe new monolayer freezing shaft lining during freeze sinking are obtained through stressanalysis. In addition, after analyzing the variation of total radial interaction forcef_x, thetechnical measures are also promoted to avoid the tensile stress between shaft lining and bedrockwhen frozen wall thawing.Aiming at the three probable leaking channels of the new monolayer freezing shaft lining,firstly, the generation mechanism of shaft lining cracks during shaft sinking is described. Then,through numerical analysis and field measurement, the key construction technologies used innew monolayer freezing shaft lining in the bedrock are discussed detailedly. The research resultsshow that:1) When the distance between freezing pipes and sidewall D_f≥3m and sidewalltemperature t_b≥-5℃, the positive temperature curing time of shaft lining can be ensured to begreater than or equal to26.7d;2) When the gradually stabilized concrete expansion strain tisnot less than300μ and the28-day expansion strain is not less than50%(i.e.150μ), thetangential and vertical temperature cracks in shaft lining can be avoided;3) Verticalreinforcement preload can take the value of20kN, and the pre-tightening process should becompleted before concrete is poured to half of construction segment height;4) Radial interactionforce f_aplays a significant role in controling temperature tensile stress of the shaft lining;5)"Top-down concentrated grouting process" is suggested for new-old concrete interf_acegrouting. The grouting pressure should be taken as1times the hydrostatic pressure;6) If thenew-old concrete interf_ace do not leaking for about3minute and grouting pressure do notdecrease, then the effect of grouting can be thought good.Based on the project example of Hulusu auxiliary shaft of Hujierte coal mine in Erdos, theconstruction technology and monitoring method of the first new single-layer shaft lining are described in bed rock during freeze sinking in China. The In-situ monitoring results show that:1) The freezing pressure is mainly affected by rock moisture content and rock strength, but therocks buried deep H affects little;2) The measured value of Pmaxis1.08~1.74MPa. Pmaxis muchsmaller than hydrostatic pressure P0and the maximum freezing pressure Pωin deep alluvium;3) The maximum stress of vertical steels is less than70.8MPa and the maximum stress of hoopsteels is less than101.0MPa. The maximum stress is only equal to about1/3of the strengthdesign value300MPa of reinforcement HRB335.4) Among the in-situ measurement stratumsF1~F3, the extreme compressive strain is just only25.7%,19.2%and19.0%of the concreteultimate compressive strainmax.5) In conclusion, the new single-layer shaft lining of Hulusuauxiliary shaft is in safe status during shaft freezing sinking.Finally, the key construction technologies are summarized for the new monolayer freezingshaft lining in bedrock. The research results can provide a reference for field technicians andhave important reference value for follow-up application of the new monolayer shaft lining.更多还原