张家沟危岩裂缝变化规律及温度干扰排除研究

Evolutionary regularity and temperature interference elimination of the cracks in Zhangjiagou rockfall

采用裂缝计对忠武管道张家沟段危岩裂缝进行了近3 a的相对位移监测,变形曲线经历了收缩-扩张的＂类正弦＂变化过程。由相关性分析可知,裂缝相对位移实测值与同期温度呈明显负相关性,因此可以推断温度是引起实测曲线呈年周期性变化的主要原因,且裂缝相对位移变化滞后温度变化3~12 h。根据这一特点,采用线性回归分析方法消除了由温度引起的岩体线弹性假象位移,反映了危岩裂缝变形的真实状态。

The present paper is aimed to introduce our case study of the deformation regularity and the temperature interference of the cracks along the Zhangjiagou pipeline section from Zhongxian county to Wuhan city.In doing our research,we have observed the relative displacement of main tensile cracks at trailing edge of the falling rocks,which are monitored by using a crack meter for almost 3 years.The results of our monitoring activities of the above said rocks help us to gain large amounts of data and information on the crack-deformation changing regularity and the deformation-displacement curve per year and the temperature change in the same period.Such monitoring activities and observations enable us to draw bit by bit the changing or evolutionary regularities of the relative displacement taking place in the form of contraction（expansion（deformation in the form of ＂class sine＂.And in turn the correlation analysis of the relative displacement of cracks and the temperature effect on the rocks during the same period helps us to prove that there exists a significant negative correlation between the two.Therefore,it can be said that the change of temperature may account for the ＂class sine＂ displacement in the measured displacement curve.Besides,we have adopted the daily deformation data at three time spots,i.e.9：00,12：00,15：00 in order to trace the hysteresis between the relative displacement and temperature.And then the tracing,measuring results and recorded data indicate that the temperature at noon is highest during the day,but the maximum relative displacement taking place in the afternoon.Therefore,it can be inferred that the evolutionary displacement shows hysteresis to the temperature with 3-12 hours.As to the effect of temperature on the deformation of cracks,we have adopted the linear regression analysis method in this paper to remove the linear elastic illusion displacement caused by the temperature change and the reflected development state of rockfall cracks correctly.The interference eliminated curve shows the relative displacement in the form of expanding and contraction respectively,though the relative displacement is insignificant.In conclusion,it can be said that the installation position of crack meter and the evolutionary stage of rockfall cracks are the two main mechanisms responsible for the curve form of the actual evolutionary state of the cracks.