极端大温差、干旱戈壁地区桥墩养护方法研究

针对兰新铁路第二双线沿线大温差、戈壁地区恶劣的气候环境,论证了桥墩采取特殊保温养护措施的必要性,并对常用保温材料及提出的橡塑板保温材料进行机理分析、数值计算、应用实例论证,最终选择保温性能良好的柔性保温绝热橡塑板,并辅以土工布保湿进行养护.根据理论及模拟计算确定的保温材料,对比两种具有代表性的养护方式(土工布+橡塑板包裹、塑料布+棉布+彩条布包裹)对桥墩温差及温度应力的影响,结合室内和现场试验,结果表明:常规的养护方式难以满足要求,通过橡塑板保温材料的应用,可以把桥墩水化热里表温差控制在20℃规范要求内,保证混凝土不因里表温差过大,而导致混凝土桥墩开裂.根据研究成果,提出了现场桥墩养护的指导性意见.大温差、干旱戈壁地区桥墩保温养护试验研究为兰新铁路第二双线桥墩养护提供了理论支持和实践经验,也提出了一种橡塑板包裹养护桥墩的新方法.

Research on Method of Pier Maintenance in Gobi Region of Extreme Large Temperature Difference and Drought

According to the particularity of climate environment of large temperature and difference in gobi region along the second double line of Lan-Xin Railway,the necessity of pier insulation maintenance is demonstrated,the common insulating material and rubber board heat preservation material are analyzed by mechanism analysis and numerical calculation,and they are demonstrated by application example.The flexible rubber board is chosen for its good insulation,and the geo-textile is used for curing.The data collected is analyzed to contrast the influence of two represent-ative maintenance ways （geotextile＋rubber board package and plastic＋cotton＋striped cloth package）on temperature and stress of pier by the interior of insulating material and combining with the application example.The results indicate that the regular maintenance way is difficult to meet the requirements,and the application of rubber board which is heat preservation material can make the pier＆#39;s hydration heat temperature of internal-external temperature difference at 20 ℃.It can guarantee specification requirements of internal-external temperature difference and can avoid excessive temperature arousing concrete cracking of concrete pier.Finally,according to the re-search results,the pier maintenance opinions are put forward.The test research of pier insulation maintenance in gobi region of extreme large temperature difference and drought provides theoreti-cal support and practical experience for pier maintenance on the second double line of Lan-Xin Railway.Furthermore,a new method is put forward for pier maintenance of the rubber and plastic board package.