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非均质围岩中,水工压力隧洞混凝土衬砌间距不等,裂缝位置未知。建议一个能够确定初裂裂缝位置的数值计算方法,并利用现场试验结果验证了其可行性。阐明了典型地质条件对衬砌最大应力位置,即第一条裂缝位置的影响。通过大量计算,分析了混凝土开裂所引起的释放应力的特性,从而得出压力隧洞混凝土衬砌有关初裂间距的某些概念:相同围岩条件下,大直径压力隧洞混凝土衬砌的初裂裂缝条数少于小直径隧洞;洞径相同条件下,非均质围岩中混凝土衬砌的初裂裂缝条数少于均质围岩隧洞;各计算情况下,混凝土的初裂裂缝条数为1条4条,裂缝条数较少的主要原因是开裂时,围岩对衬砌的平均切向抗力较小(约为0.05MPa)和应力松弛范围较大,约90°。
In heterogeneous surrounding rock, hydraulic pressure tunnel concrete lining spacing, fracture location unknown. A numerical method to determine the location of primary cracks is proposed, and its feasibility is verified by the field test results. The effects of typical geological conditions on the location of the maximum stress in the lining, ie the location of the first crack, are clarified. Through a large number of calculations, the characteristics of release stress caused by concrete cracking are analyzed, and some concepts about the initial cracking distance of concrete tunnel lining are obtained. Under the same surrounding rock conditions, the number of primary cracking cracks in concrete lining of large diameter pressure tunnel Less than the small-diameter tunnel; under the same hole diameter, the number of primary cracks in the concrete linings in the heterogeneous surrounding rock is less than that of the homogeneous surrounding rock tunnels. In each calculation, the number of primary cracks in the concrete is 1 The main reason that the number of cracks is small is that the average tangential resistance of the surrounding rock to the lining is small (about 0.05MPa) and the stress relaxation range is large, about 90 °.