复合土钉支护在近接高速公路基坑工程中的应用

    Application of a Composite Soil Nailing System in Excavation Engineering Close to an Expressway

    • 摘要: 复合土钉支护结构可以减小基坑变形,防止紧邻道路、管线、建(构)筑物产生较大变形.给出土钉与锚杆、微型桩复合支护在近接高速公路基坑工程中应用实例,阐述该工程的设计、施工、监测技术要点.考虑高速公路汽车荷载计算了不同工况的基坑稳定安全系数,给出变形控制标准及控制措施.针对碎石和填土分层交替填筑、软硬不均地层,采用套管跟进进行钻孔,有效克服了卡钻现象.监测表明,基坑顶部高速公路路面最大水平位移控制在了10mm以内,满足控制标准的要求;锚杆支护是控制水平位移的有效措施.

       

      Abstract: The composite soil nailing systems are considered to be effective to reduce deflections of excavations,so that they can be applied to the excavated cases which are close to roads,pipes,and structures where surrounding strate movements are not permitted.A case of application of the composite retaining structure of soil nails,anchors and micro-piles in excavation engineering close to an expressway,was demonstrated.The technical essentials of design,construction,and field measurement of the engineering were expounded in considerable detail.The stability analysis was carried out based on different engineering cases considering load distribution of expressway automobiles and the deflection control standards and measures were drawn up.The anchor hole was bored by pushing jacket tube to prevent drill bit from being withheld in the uneven distributed subsoil which consisted of gravel and clay filling to be filled layer by layer.The measured data shows that the maximum horizontal displacement of the expressway pavement on the excavation top is limited to the value less than 10 mm and meets the requirements of deflection control standard,and the pre- stressed anchors are effective measures to control the horizontal displacements.

       

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