高压岔管衬砌混凝土施工期温控防裂研究

Research on Temperature Control and Cracking Prevention during the Construction Period of Lining Concrete of High-pressure Bifurcated Pipe

高压岔管承受高压水和高速水流冲刷,为了满足这一结构和工作特点,混凝土常采用泵送混凝土,利用其强度高的优点,但其温升高、弹性模量大,且一般是早强混凝土,容易产生温度裂缝。针对这一问题,以阳江抽水蓄能电站高压岔管为例,结合结构和材料特点,借助三维有限单元法,对高压岔管施工期的温度应力进行研究,筛选温控防裂措施。计算结果表明,高压岔管分缝长度对防裂影响显著,同时降低入仓温度,采用内部通水降温,可起到更好的温控防裂效果。高压岔管混凝土在有通水冷却措施条件下,浇筑温度控制在26℃以内,最小安全系数可达1.50以上,可作为工程现场浇筑施工方案。

The high-pressure bifurcated pipe is subject to the scour of high pressure and high speed water flow.In order to meet the structural and working characteristics,the pumping concrete is often used to make use of its advantage of high strength,but because of its high temperature rise and large elastic modulus,and generally early strength concrete,this concrete is easy to produce temperature cracks.In order to solve this problem,the high-pressure bifurcated pipe of Yangjiang Pumped-storage Power Station is taken as the example,the temperature stress of high-pressure bifurcated pipe during the construction period is studied combined with the characteristics of structure and material and with the help of three-dimensional finite element method,and the temperature control and cracking prevention measures are selected.The calculation results show that the design length of bifurcated pipe joint has a significant effect on cracking prevention,and at the same time,reducing the pouring temperature and adopting internal water cooling can achieve better effect of temperature control and cracking prevention.Under the condition of water cooling measures,if the pouring temperature of high-pressure bifurcated pipe concrete is controlled within 26℃,the minimum safety factor can be above 1.50,which can be used as the pouring construction scheme of engineering site.