大跨度公路隧道围岩竖向压力分布特征探讨

Analysis of Largespan Highway Tunnel Surrounding Rock Vertical Pressure Attributes

摘要:

结合龙头山大跨度隧道围岩压力监测,探讨了竖向压力与隧道埋深、围岩级别的关系;并采用深、浅埋隧道法、普氏系数法以及别尔巴乌麦尔法分别对不同的监测断面计算其围岩压力,对于高级别围岩Ⅳ、Ⅴ,普氏系数法计算结果和实测值较为吻合,而深、浅埋隧道法和别尔巴乌麦尔法计算结果比较一致,但是均大于实测值;对于Ⅱ、Ⅲ围岩,深、浅埋隧道法与实测值较为吻合,普氏系数法要小于实测值,而别尔巴乌麦尔法则大于实测值;从围岩压力与埋深的关系可以看出,深、浅埋隧道法、别尔巴乌麦尔法与实测值的变化趋势基本一致,但比实测值偏大,普氏系数法则比较接近于实测压力的平均值.根据不同的计算方法讨论了不同计算方法对大跨度隧道的适用性,为大跨度隧道围岩压力的设计计算提供有意义的参考.

Abstract:

Based on the monitoring of the Longtou Mountain largespan tunnel surrounding rock pressure,a study is made of the relationship of vertical pressure,buried depth and surrounding rock grade.The road tunnel design code method,M M theory method and Bilbawumyer theory method are respectively used to calculate the surrounding rock pressure.In the rock grades IV or V,the value calculated by M M theory method and the actual value are about the same,the value calculated by the road tunnel design code method and the value calculated by Bilbawumyer theory method are greater than the actual value; in the rock grade Ⅱ or Ⅲ,the value calculated by the road tunnel design code method and the actual value are about the same,the value calculated by M M theory method value is smaller than the actual value,and the value calculated by Bilbawumyer theory method is greater than the actual value; in the relationship of surrounding rock pressure and buried depth,the variation trends of the road tunnel design code method value and Bilbawumyer theory method value are similar to the actual value,but they are greater than the actual value.the value calculated by M M theory method is close to the average actual value.The applicability of different calculation methods of surrounding rock pressure is studied for the largespan tunnel,which provides a reference for largespan tunnel design.