ISSN 1000-3665 CN 11-2202/P

    川藏铁路某特大桥成都侧岸坡工程地质特征及稳定性评价

    Slope engineering geology characteristics and stability evaluation of a grand bridge to Chengdu bank on the Sichuan-Tibet Railway

    • 摘要: 拟建的川藏铁路某特大桥是一座重要的控制性桥梁,其桥址区的地质安全风险评价具有重要的工程意义。该特大桥成都侧岸坡三面临空,海拔高差大,岩性复杂多变,岩体结构和完整性差,风化卸荷强烈,浅表部危岩体发育,调查表明成都岸八曲侧斜坡曾发生较大规模顺层岩质崩滑。采用遥感解译、剖面测量及稳定性计算等技术方法,调查成都侧岸坡地形地貌、地层岩性、结构面发育及变形破坏等特征,分析评价特大桥成都岸八曲侧顺层岩质斜坡稳定性。结果表明:天然和暴雨工况下,斜坡稳定系数大于1.1;强震(PGA>0.3 g)工况下,斜坡稳定系数小于1.0,可能出现局部或整体失稳破坏。建议在清除斜坡表部危岩体的基础上,进一步深入研究八曲侧顺层岩质斜坡未来可能出现的变形破坏范围和程度,提出针对性工程防治措施建议。

       

      Abstract: The planned grand bridge is an important control bridge along the Sichuan-Tibet Railway. A large- scale bedding rock collapse occurred on the slope of the Baqu river side of Chengdu bank, with the protruding ridge, high elevation difference, complex and changeable lithology, poor rock mass structure and integrity, highly weathering and unloading and potential unstable rock mass on the surface of the slope. This paper investigates the topography and geomorphology, stratum lithology, discontinuities development and the characteristics of deformation and failure of the bank slope to Chengdu by remote sensing interpretation, profile measurement and stability calculation. The stability of bedding rock slope of the Baqu river side of Chengdu bank under natural and rainstorm conditions are analyzed and evaluated. The results show that the safety factor of slope stability is greater than 1.1; under the strong earthquake (PGA>0.3 g) conditions, the safety factor of slope stability is less than 1.0, and local or overall instability may occur. Based on removing the dangerous rock mass on the surface of the slope, it is suggested that the possible failure range and degree of the bedding rock slope on the Baqu river side should be further studied and the engineering prevention measures should be put forward.

       

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