| 点荷载仪在优化红层隧道围岩级别中的应用 |
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| 引用本文： | 彭国喜,徐天爱,刘鹤冰,蒋良文,袁传保.点荷载仪在优化红层隧道围岩级别中的应用[J].路基工程,2023,0(2):158-162. |
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| 作者姓名： | 彭国喜 徐天爱 刘鹤冰 蒋良文 袁传保 |
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| 作者单位： | 1.中铁二院工程集团有限责任公司，成都 610031 |
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| 摘 要： | 目前，在划分隧道围岩级别时，多是采用岩石饱和抗压强度来计算围岩BQ值，致使红层地区的隧道Ⅴ级围岩偏长，PPP高速公路项目的投资压力偏大。按照岩石中“砂质含量”从低到高的顺序，将红层岩石主要分为“泥岩、砂质泥岩、泥质砂岩、砂岩”四类，分析红层隧道的工程地质特征，判断出“岩石强度Rc是影响红层隧道围岩BQ值的关键因子”；分析了“样品失真”是导致常规抗压试验数据偏于保守的根本原因；归纳了点荷载试验具备“设备轻便、取样快捷、离散性小”等优点，阐明采用天然状态下的岩石点荷载强度来计算BQ值更贴合红层隧道实际水文地质条件的原理；建立了采用“点荷载强度”来优化红层隧道围岩的方法。
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| 关 键 词： | 红层隧道 掌子面 BQ值 岩石点荷载仪 抗压强度 |
| 收稿时间： | 2023-02-09 |
Application of Point Load Apparatus in Optimizing the Surrounding Rock Classification of the Red Layer Tunnel |
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| Abstract: | At present, the saturated compressive strength of rock is used to calculate the BQ value of surrounding rock while classifying the surrounding rock of the tunnel, resulting in the longer V-class surrounding rock of the tunnel and higher investment pressure of PPP highway projects in the red layer area. It classifies red layer rocks into "mudstone, sandy mudstone, argillaceous sandstone and sandstone" according to the "sandy content" of rocks from low to high, concludes that "rock strength Rc is the key factor affecting BQ value of surrounding rock in red layer tunnel" by analyzing the engineering geological characteristics of the tunnel, and finds that "sample distortion" is the root cause of the conventional compressive test data being conservative. In addition, this paper summarizes the advantages of "light weight, efficient sampling and small dispersion" of point load test, clarifies the principle that it is more suitable for the actual hydrogeological conditions of red layer tunnel to calculate the BQ value by using the point load strength of rocks under the natural state, and establishes the method of "point load strength" to optimize the surrounding rock of the red layer tunnel. |
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