微型抗滑桩加固边坡极限抗力研究
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摘要
研究目的:微型抗滑桩具有桩位布置灵活、施工速度快、对施工场地适应性强、对环境影响小等优点,近年来在边坡加固领域得到广泛应用和推广,但目前缺乏分析微型抗滑桩加固边坡极限抗力的科学方法。基于此,本文采用数值分析手段建立微型抗滑桩加固边坡的极限抗力分析模型,以桩身弯曲承载力、剪切承载力和结构位移为控制条件,提出一种微型抗滑桩加固边坡极限抗力的分析方法,并进行力学机制研究。研究结论:(1)不同类型边坡微型抗滑桩提供的极限抗力有所不同,岩土强度越高微型抗滑桩提供的极限抗力越大,整体而言,对于土质边坡,微型抗滑桩的极限抗力主要受桩身弯曲承载力控制;对于岩质边坡,微型抗滑桩的极限抗力主要受剪切承载力控制;(2)滑坡推力主要由靠近荷载的半幅桩承载,远离荷载的半幅桩基本不受力;(3)微型抗滑桩与岩土的接触反力主要由靠近荷载桩单元的正应力提供,剪应力的影响不大;(4)该研究成果可为微型抗滑桩在边坡加固工程中的设计和安全评价提供理论依据。
Research purposes: The antislide micropile has the advantages of flexible arrangement,fast construction,strong adaptation to the construction site and marginal environment impact. In recent years,the antislide micropile has been widely used and popularized in the field of slope reinforcement. However,there is no scientific method to analyze the ultimate resistance of the micropile in slope stabilization at present. Therefore,a simplified numerical model for analyzing the resisting force of the micropile is set up and an approach is proposed to calculate the ultimate resistance under the controlling of bending bearing capacity,shear bearing capacity and pile horizontal displacements. The loading mechanism is studied by the proposed method.Research conclusions:( 1) The ultimate resistance of micropile is different with type of slope materials,and for the higher strength of slope,the micropile provides the greater ultimate resistance. In general,the ultimate resistance of the antislide micropile is mainly controlled by the bending capacity and shear capacity of the pile section for the soil and rock slope,respectively.( 2) The thrust is mainly carried by the half-piles near the load,and the half-piles away from the load are not subject to force.( 3) The resistance between the micropile and soil is mainly provided by the normal stress of the pile elements near the load,and the shear stress has a marginal and negligible effect.( 4) The research resultsprovide theoretical guidance for the design and safety evaluation of antislide micropile in slope engineering.
Research purposes: The antislide micropile has the advantages of flexible arrangement,fast construction,strong adaptation to the construction site and marginal environment impact. In recent years,the antislide micropile has been widely used and popularized in the field of slope reinforcement. However,there is no scientific method to analyze the ultimate resistance of the micropile in slope stabilization at present. Therefore,a simplified numerical model for analyzing the resisting force of the micropile is set up and an approach is proposed to calculate the ultimate resistance under the controlling of bending bearing capacity,shear bearing capacity and pile horizontal displacements. The loading mechanism is studied by the proposed method.Research conclusions:( 1) The ultimate resistance of micropile is different with type of slope materials,and for the higher strength of slope,the micropile provides the greater ultimate resistance. In general,the ultimate resistance of the antislide micropile is mainly controlled by the bending capacity and shear capacity of the pile section for the soil and rock slope,respectively.( 2) The thrust is mainly carried by the half-piles near the load,and the half-piles away from the load are not subject to force.( 3) The resistance between the micropile and soil is mainly provided by the normal stress of the pile elements near the load,and the shear stress has a marginal and negligible effect.( 4) The research resultsprovide theoretical guidance for the design and safety evaluation of antislide micropile in slope engineering.
引文
[1]Bruce D A,Dimillio A F,Juran I.Micropiles:the State of Practice Part I:Characteristics,Definitions and Classifications[J].Ground Improvement,1997(1):25-35.
[2]Lizzi F.Special Patented Systems of Underpinning and more Generally,Subsoil Strengthening by Means of Pali Radice(Root Piles)with Special Reference to Problems Arising from the Construction of Subways in Built-up Area[R].Special Lecture Given at University of Illinois at Urbana-Champaign,1971.
[3]Turner J P,Halvorson M.Design Method for Slidestabilizing Micropile Walls[C]//Geo-Congress 2013,ASCE,2013,San Diego,California,USA.
[4]冯君,周德培,江南,等.微型抗滑桩体系加固顺层岩质边坡的内力计算模式[J].岩石力学与工程学报,2006(2):284-288.Feng Jun,Zhou Depei,Jiang Nan,etc.A Model for Calculation of Internal Force of Micropile System to Reinforce Bedding Rock Slope[J].Chinese Journal of Rock Mechanics and Engineering,2006(2):284-288.
[5]孙书伟,朱本珍,郑静.基于极限抗力分析的微型抗滑桩群加固土质边坡设计方法[J].岩土工程学报,2010(11):1671-1677.Sun Shuwei,Zhu Benzhen,Zheng Jing.Design Method of Micropile Group for Soil Slope Stabilization Based on Ultimate Resistance of Analysis[J].Chinese Journal of Geotechnical Engineering,2010(11):1671-1677.
[6]孙书伟,朱本珍,马惠民,等.微型抗滑桩群与普通抗滑桩抗滑特性的对比试验研究[J].岩土工程学报,2009(10):1564-1570.Sun Shuwei,Zhu Benzhen,Ma Huimin,etc.Model Tests on Anti-sliding Mechanism of Micropile Groups and Anti-sliding Piles[J].Chinese Journal of Geotechnical Engineering,2009(10):1564-1570.
[7]ITASCA CONSULTING GROUP.FLAC3D 5.0Manual[M].Itasca Consulting Group,Minneapolis,2012.
[8]TB 10025—2006,铁路路基支挡结构设计规范[S].TB 10025—2006,Code for Design on Retaining Structures of Railway Subgrade[S].
[2]Lizzi F.Special Patented Systems of Underpinning and more Generally,Subsoil Strengthening by Means of Pali Radice(Root Piles)with Special Reference to Problems Arising from the Construction of Subways in Built-up Area[R].Special Lecture Given at University of Illinois at Urbana-Champaign,1971.
[3]Turner J P,Halvorson M.Design Method for Slidestabilizing Micropile Walls[C]//Geo-Congress 2013,ASCE,2013,San Diego,California,USA.
[4]冯君,周德培,江南,等.微型抗滑桩体系加固顺层岩质边坡的内力计算模式[J].岩石力学与工程学报,2006(2):284-288.Feng Jun,Zhou Depei,Jiang Nan,etc.A Model for Calculation of Internal Force of Micropile System to Reinforce Bedding Rock Slope[J].Chinese Journal of Rock Mechanics and Engineering,2006(2):284-288.
[5]孙书伟,朱本珍,郑静.基于极限抗力分析的微型抗滑桩群加固土质边坡设计方法[J].岩土工程学报,2010(11):1671-1677.Sun Shuwei,Zhu Benzhen,Zheng Jing.Design Method of Micropile Group for Soil Slope Stabilization Based on Ultimate Resistance of Analysis[J].Chinese Journal of Geotechnical Engineering,2010(11):1671-1677.
[6]孙书伟,朱本珍,马惠民,等.微型抗滑桩群与普通抗滑桩抗滑特性的对比试验研究[J].岩土工程学报,2009(10):1564-1570.Sun Shuwei,Zhu Benzhen,Ma Huimin,etc.Model Tests on Anti-sliding Mechanism of Micropile Groups and Anti-sliding Piles[J].Chinese Journal of Geotechnical Engineering,2009(10):1564-1570.
[7]ITASCA CONSULTING GROUP.FLAC3D 5.0Manual[M].Itasca Consulting Group,Minneapolis,2012.
[8]TB 10025—2006,铁路路基支挡结构设计规范[S].TB 10025—2006,Code for Design on Retaining Structures of Railway Subgrade[S].