混凝土强度等级和类型对地下厂房岩锚梁混凝土温控的影响

Influences of Concrete Strength Grade and Type on Temperature Control of Rock-anchored Beam Concrete

利用有限元法,对某水电站地下厂房岩锚梁进行三维有限元仿真计算。通过比较岩锚梁中间断面代表点的最高温度、早期最大拉应力、最小抗裂安全系数等,分析不同混凝土强度等级和类型对岩锚梁混凝土温度场与温度应力场的影响规律。研究结果表明,混凝土强度等级越高,岩锚梁混凝土的最高温度、最大内表温差、最大拉应力值越大,最小抗裂安全系数越小;相对于常态混凝土,泵送混凝土各特征值均偏向于不利,温控防裂措施要求更加严格。

The three-dimensional finite element simulations are carried out on rock-anchored crane beam in an underground powerhouse of hydropower station by using finite element method. By comparing the maximum temperature, the maximum early tensile stress and the smallest crack safety factor of middle point in represented cross-section of the beam, the influences on concrete temperature and stress fields by the changes of concrete strength grade and type are analyzed. The results show that, （a） if the concrete strength gets greater, the maximum temperature, maximum internal temperature difference and the maximum tensile stress of rock-anchored crane beam concrete will get greater, but the minimum safety factor will be smaller; and （b） comparing to normal concrete, the characteristic values of pumping concrete trend to disadvantage, so more strict temperature control measures are required.