明挖下沉式高速公路隧道混凝土施工仿真与温控方案研究

Research on construction simulation and temperature control scheme of open cut and sinking expressway tunnel concrete

温度裂缝是下沉式高速公路隧道混凝土防裂的重点。结合实际对广州新白云国际机场第二高速公路明挖下沉式高速公路隧道暗埋段混凝土进行施工仿真研究,分析温度场和应力场。发现在环境温度33℃浇筑的情况下,混凝土内部过大的温度应力会引起各部位产生裂缝。实施在水管冷却措施后(20℃时浇筑,通水时间为2 d,通水水温为12℃),结果表明混凝土内部最高温度仅约39℃,各方向混凝土内部拉应力均低于强度设计值。采取该温控措施,可有效控制混凝土的温升和温度应力,降低了混凝土隧道开裂风险。

To prevent the thermal crack is always the focus of the crack problem of concrete tunnel.Combining with the actual situation,the construction simulation of the buried tunnel in the second highway of Guangzhou New Baiyun International Airport is studied,and the temperature field and stress field are analyzed.The results show that the temperature stress inside the concrete is too large,and will cause cracks,in the case of construction under the environmental temperature 33℃.While in the case of the pipe cooling(the pouring temperature is 20℃,the water supply lasts 2 days,the water temperature is 12℃),the maximum internal temperature of concrete is only about 39℃,and the internal tensile stress of concrete in all directions are lower than the design value of strength.The temperature control measures can effectively control the temperature rise and temperature stress of concrete,so the risk of concrete tunnel cracking is reduced.