基于现场实测的深埋风积沙隧道围岩压力计算方法研究

风积沙作为一种黏聚力低、自稳能力差的不稳定围岩,给隧道设计和施工带来很大困难。 为探究风积沙围岩压力大小和分 布规律,依托蒙华铁路王家湾隧道开展现场量测试验,根据实测的围岩压力分布特征,得到深埋风积沙隧道的围岩压力计算模式, 并通过数值计算分析与现场量测数据对比验证其合理性。 研究结果表明: 深埋风积沙地层围岩压力分布很不均匀,但普遍拱部较 小,初期支护大部分处于受压状态。 计算分析得深埋风积沙隧道围岩压力采用太沙基计算公式是较为合理的,进一步优化得深埋 风积沙隧道垂直方向围岩压力计算图示采用“双峰”形分布,水平方向围岩压力计算图示采用“阶梯”形分布,相比铁路隧道设计规 范的传统模式更安全,与实际衬砌受力状态更符合。

Calculation Method for Surrounding Rock Pressure of Deep Aeolian Sand Tunnel Based on Field Measurement

Aeolian sand is a kind of unstable surrounding rock with low cohesion and poor self-stability, which brings great difficulties to tunnel design and construction. Hence, field measurement experiments are carried out on Wangjiawan Tunnel on Menghua Railway to explore the pressure and distribution law of surrounding rock in aeolian sand. The calculation model of the surrounding rock pressure of deep aeolian sand tunnel is obtained based on the distribution characteristics of surrounding rock pressure, and its rationality is verified by numerical analysis and field measurement data. The research results show that the distribution of surrounding rock pressure in deep aeolian sand is very uneven, but generally small at arch, and most of the primary support is under pressure. The calculation analysis results show that the Terzaghi theory is more rational in calculating tunnel surrounding rock pressure. The vertical surrounding rock of aeolian sand tunnel shows a double-peak shape, and the horizontal one shows a gradual increase shape. The calculation diagrams obtained are safer than the traditional mode of the railway tunnel design specification, which are more in line with the actual lining stress state.