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西南山区高等级公路岩质边坡稳定性分级研究

Study on Highway Slope Rock Mass Rating in South-West Mountain Area, China

【作者】 王哲

【导师】 刘汉超; 柴贺军;

【作者基本信息】 成都理工大学 , 地质工程, 2004, 硕士

【摘要】 高等级公路建设勘测阶段工期紧迫、一般难以在对每一个工点的地质条件及岩体力学特征作详细勘测后进行稳定性计算分析工作。边坡岩体分级系统以其简便、快速的特点,在公路边坡稳定性评价领域具有广泛应用前景。本文在对西南地区几条在建高等级公路实地采集的100余个边坡样本进行统计分析后,结合公路边坡的特点,将SMR-CSMR体系改进,提出了适宜于公路边坡稳定性评价实践的HSMR系统(Highway Slope Mass Rating)。 1.根据分级结果对比发现,Q系统具有分级指标获取困难的特点,且未能考虑边坡走向、坡角与结构面组合情况及坡高等因素对边坡稳定性的影响,难以适应边坡工程中稳定性评价的要求。SMR法在RMR分类体系的基础上合理地考虑了结构面产状及其与临空面的组合情况对边坡稳定性的影响,另外将边坡开挖方式作为参评因子,较全面地考虑了各种影响因素的综合作用。但由于未考虑坡高等因素,SMR评分值较边坡实际稳定状况低5~10个分值。CSMR法引进了坡高修正系数以补充SMR法未考虑边坡高度的欠缺,但由于坡高修正系数取值不合理,所以分值普遍偏高。 2.根据公路边坡自身的特点,结合力学分析,运用数理统计分析手段,将坡高修正系数进行改进,使之更加合理地反映了公路边坡坡高对边坡稳定性的影响。首次将不同岩性组合形式对边坡稳定性的影响以岩性组合系数的形式引入边坡稳定性分级系统,并将结构面修正系数进行局部调整,提出了针对公路边坡的HSMR分级体系。 3.提出“合理开挖坡角”的概念,经统计分析后建立了合理开挖坡角与HSMR的量化关系,并对不同稳定级别的边坡作出相应开挖坡角的建议。在分析各稳定级别边坡可能破坏模式的基础上,根据公路行业通常采用的支护手段,提供更详细、更具针对性的系统化边坡治理措施建议。 4.对边坡稳定性分级细则进一步规范和明确化,有助于形成统一标准,使得评分结果更加客观、准确,利于保证系统的可靠性。 5.对典型样本的校验结果显示,HSMR系统分级结果与边坡实际稳定状况最为接近,建议治理措施和合理开挖坡角对于工程实践具有一定的参考意义。同时,该系统具有操作简便,指标易于提取等特点,能基本满足公路边坡稳定性初步评价的需要。

【Abstract】 On account of limited time of highway construction, we can hardly explore geologic status and rock mass mechanic character for all slopes in detail, before a stability analysis. Slope rock mass rating system, a convenient method, sees a bright future in the field of highway slope stability evaluation. More than 100 highway slopes collected from south-west area of China are analyzed statistically in this paper. A new slope stability system HSMR (Highway Slope Mass Rating), improved from SMR-CSMR, is given here.1). There are many difficulties in getting parameters when using Q system. In addition, the compound of strike, angle of gradient and discontinuities were not taken into consideration. Therefore, the system is hard to appraise slope stability precisely. In SMR system, the relation between discontinuities and slope freeing face was considered, so was excavating method. However, slope height was omitted in this system. As a result, SMR is 5-10 point lower than that of actual stability. Based on SMR, CSMR system has adopted slope height coefficient, to show the relation between slope height and slope stability. However, the coefficient is unreasonable to highway slope, so CSMR is higher on average.2). After a mechanical analysis, slope height coefficient was updated by statistical means. The amended coefficient is more effective for evaluating the effect of highway slope height. For the first time, multiple lithology factor, was brought into slope stability rating system. The values of different discontinuities’ coefficients were partly modified. HSMR system for highway rock slope was presented here.3). A quantitative relation between befitting gradient and HSMR was established by statistic means, and a corresponding gradient to different stability level was suggested. Through a analysis of possible failure styles relative to different stability levels, this paper gave some detailed systematized advice on slope support patterns, which are widely used in highway engineering.4). Standardizing detailed rules about slope stability rating, what made for a uniform standard, and helps to an objective result. Accordingly, reliability of this system was ensured.5). Verifying typical samples showed that HSMR is preciser than other rock mass rating systems when estimating highway slope stability, besides, support patterns and befitting gradient suggested provide engineer a effective reference to rock slope design. Characterized by convenience, HSMR system can satisfy preliminary stability evaluation to highway slope well.

  • 【分类号】U416.1
  • 【被引频次】27
  • 【下载频次】491
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