温度变化对CPⅢ平面测量结果的影响

Influence of temperature changes on the CP III plane measurements

目前我国高速铁路建设里程已达3万余公里,在全球首屈一指。在高铁建设过程中,轨道控制网(CPⅢ)测量是一项必不可少的工作。某高铁CPⅢ建网测量过程中,相同点位搭接时两次测量结果坐标较差较大,不满足规范搭接要求,需进行外业补测。本文对搭接不成功处的数据进行了分析,认为两次测量温差较大可能是导致搭接不成功的原因之一,温度变化会对CPⅢ测量结果产生影响。同时,梁体宽度确定时引入混凝土膨胀系数计算得到的梁体宽度变化值与实测值互差较小,均未超过0.7 mm,验证了本文的观点。根据气温变化调整补测时间后,数据成果满足规范要求。最后通过定量分析得出,若将梁体宽度变化阈值设置为±2 mm,梁体宽度为9.25 m时,两次测量温差不应超过-21.6℃~21.6℃;梁体宽度为12.20 m时,两次测量温差不应超过-16.4℃~16.4℃。

The mileage of constructed high-speed railways in China has reached over 30,000 kilometers,that ranking the first in the world.Before the production of ballastless track bed,the track control net‐work(CP III)measuring is an essential task.It is found in the construction of a high-speed railway CPⅢnetwork that the coordinate difference between the two measurements at the lap area is large and field remeasuring is needed.By analyzing these data,it is concluded that the significant temperature dif‐ference between the two measurements could be one of the reasons for the unsuccessful overlap,tem‐perature changes can have an impact on the measurement results of CP III.The calculated width varia‐tion of the beam based on the concrete expansion coefficient shows minimal deviation from the mea‐surements,none of them exceeds 0.7 mm,thereby validating the mentioned perspectives.Finally,it con‐cluded that if the threshold of bridge beam width variation is set to±2 mm,the temperature difference between two measurements should not exceed-21.6℃~21.6℃and-16.4℃~16.4℃when the bridge beam width is 9.25 m and 12.20 m respectivelly.