小湾导流中孔闸墩开裂成因及工作性态分析

Analysis on cracking cause and working behavior of sluice piers for middle diversion outlets of Xiaowan arch dam

针对小湾拱坝在施工过程中导流中孔闸墩会产生裂缝问题,建立了一套基于弹粘塑性势理论的数值分析系统,对其开裂的原因及工作性态进行了计算分析.结果表明:开裂原因并非单一因素所致,而是温控措施、锚索张拉及蓄水的累计作用,其中温控措施产生的拉应力为最主要原因;导流中孔若继续参与导流工作,裂缝充水时,其尖端的应力强度因子将超过混凝土的断裂韧度,在水力劈裂作用下裂缝将继续扩展.该研究成果不仅为制定小湾拱坝导流方案提供了依据,对类似工程也具有一定的借鉴和参考价值.

In order to solve the problem that the cracks will appear on the sluice piers for the middle diversion outlets in the construction process of Xiaowan arch dam,a numerical analysis system based on elastic-visco-plastic potential theory was established.In addition,the cracking cause and working behavior of sluice piers were calculated and analyzed.The results indicate that the cracking is not induced by a single factor,but a cumulative effect of temperature control,anchor cable tension and impoundment,among which the tensile stress caused by the temperature control is the most important reason.If the middle diversion outlets continue to participate in the diversion process,the stress intensity factor of crack tip will exceed the fracture toughness of concrete when the cracks are filled with water.Under the hydraulic fracture effect,the cracks will continuously propagate.The present study can provide not only the basis for making the diversion scheme of Xiaowan arch dam,but also the references for the similar projects.