岩体离层作用下锚杆受力特性全历程分析
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摘要
针对岩体离层作用下锚杆受力特性全历程分析问题,基于锚固界面的双指数曲线模型,采用荷载传递方法,建立离层作用下锚杆受力特性的非线性解答,分析离层发展全历程过程中锚杆轴力和界面剪应力分布,以及岩体离层–锚杆轴力曲线的特性,并采用模型试验数据进行对比验证。结果表明:锚杆轴向应变的计算值与实测结果基本一致。离层发展过程中,锚杆轴力呈现先增大后减小的特性,且在离层发展后期具有明显的非线性特征。离层产生的锚杆轴力和界面剪应力均呈现明显的不均匀分布和非线性特征,且二者均随着离层的发展向两端传递。离层位置对锚杆的受力特性有很大影响:离层位于锚杆中心时,其两侧的锚杆轴力与界面剪应力均成对称分布,且随着离层发展的演变规律相同;离层偏离锚杆中心时,两侧锚杆轴力与界面剪应力分布则明显不同,界面剪应力在离层位置处存在着跳跃点,且锚固长度较小一侧的锚固界面先产生塑性变形直至整体滑移破坏,决定了锚杆所能承受的离层和抗拔荷载大小。研究结果为岩体离层作用下锚杆的受力分析提供了理论参考。
The full-range analysis on the mechanical characteristics of bolts in rock mass with bedding separation was performed with the bi-exponential model for anchorage interface to derive the nonlinear solution based on the load transfer method. The full-range mechanical characteristics of bolts including the relationships between the bedding separation and axial force,axial force distribution and shear stress were discussed. Validity of the proposed approach was verified by the experimental results. The results show that the calculated axial strain along the bolts has good agreement with the measured values. During the expanding process of bedding separation,the axial forces of the bolts increase initially and then decrease nonlinearly. The axial force and shear stress distribute unevenly along the bolts,and are transferred to both ends with the expanding of bedding separation. The location of bedding separation affects the mechanical characteristics of bolts significantly. The axial force and shear stress distribute symmetrically when the bedding separation locates at the middle of bolts. Otherwise,the axial force and shear stress show distinguishing distribution and evolution features at both sides,and the shear stress has a jump at the location of bedding separation. The interface with the shorter anchorage length yields the plastic deformation and even slipping failure in advance,which determines the bearing capacity of bedding separation and tensile load of bolts.
The full-range analysis on the mechanical characteristics of bolts in rock mass with bedding separation was performed with the bi-exponential model for anchorage interface to derive the nonlinear solution based on the load transfer method. The full-range mechanical characteristics of bolts including the relationships between the bedding separation and axial force,axial force distribution and shear stress were discussed. Validity of the proposed approach was verified by the experimental results. The results show that the calculated axial strain along the bolts has good agreement with the measured values. During the expanding process of bedding separation,the axial forces of the bolts increase initially and then decrease nonlinearly. The axial force and shear stress distribute unevenly along the bolts,and are transferred to both ends with the expanding of bedding separation. The location of bedding separation affects the mechanical characteristics of bolts significantly. The axial force and shear stress distribute symmetrically when the bedding separation locates at the middle of bolts. Otherwise,the axial force and shear stress show distinguishing distribution and evolution features at both sides,and the shear stress has a jump at the location of bedding separation. The interface with the shorter anchorage length yields the plastic deformation and even slipping failure in advance,which determines the bearing capacity of bedding separation and tensile load of bolts.
引文
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[8]KUMAR S,KHAN M A.A shear-lag model for functionally graded adhesive anchors[J].International Journal of Adhesion and Adhesives,2016,68:317–325.
[9]ZHENG J J,DAI J G.analytical solution for the full-range pull-out behavior of FRP ground anchors[J].Construction and Building Materials,2014,58(10):129–137.
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[12]王明恕.全长锚固锚杆机制的探讨[J].煤炭学报,1983,3(1):40–47.(WANG Mingshu.Mechanism of full-column rock bolt[J].Journal of China Coal Society,1983,3(1):40–47.(in Chinese))
[13]CAI Y,ESAKI Y,JIANG Y J.An analytical model to predict axial load in grouted rock bolt for soft rock tunnelling[J].Tunnelling and Underground Space Technology,2004,19(6):607–618.
[14]谷拴成,丁潇.巷道顶板离层对锚杆载荷影响的弹性分析[J].煤炭科学技术,2012,40(6):33–36.(GU Shuancheng,DING Xiao.Elastic analysis on roadway roof bed separation affected to bolt loading[J].Coal Science and Technology,2012,40(6):33–36.(in Chinese))
[15]LI C C.Performance of D-bolts under static loading[J].Rock Mechanics and Rock Engineering,2012,45(2):183–192.
[16]LI C,STILLBORG B.Analytical models for rock bolts[J].International Journal of Rock Mechanics and Mining Sciences,1999,36(8):1 013–1 029.
[17]谷拴成,丁潇.岩体离层对锚固体荷载影响的弹塑性分析[J].岩土力学,2013,34(9):2 649–2 654.(GU Shuancheng,DING Xiao.Elastoplastic analysis of effect of bed separation on anchored mass loading in rock mass[J].Rock and Soil Mechanics,2013,34(9):2 649–2 654.(in Chinese))
[18]黄明华,周智,欧进萍.拉力型锚杆锚固段拉拔受力的非线性全历程分析[J].岩石力学与工程学报,2014,33(11):2 190–2 199.(HUANG Minghua,ZHOU Zhi,OU Jinping.Nonlinear full-range analysis of load transfer in fixed segment of tensile anchors[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(11):2 190–2 199.(in Chinese))
[19]丁潇.巷道围岩离层下锚杆荷载传递机制及支护设计研究[博士学位论文][D].西安:西安科技大学,2016.(DING Xiao.Research on bolt load transfer mechanism under bed separation effect and its support design[Ph.D.Thesis][D].Xi?an:Xi?an University of Science and Technology,2016.(in Chinese))
[20]黄明华.岩土锚杆拉拔荷载传递分析与FRP智能锚杆监测验证[博士学位论文][D].哈尔滨:哈尔滨工业大学,2014.(HUANG Minghua.Analysis on pullout load transfer mechanism of geotechnical anchor and its validating monitor with smart FRP anchor[Ph.D.Thesis][D].Harbin:Harbin Institute of Technology,2014.(in Chinese))
[2]程良奎,范景伦,韩军,等.岩土锚固[M].北京:中国建筑工业出版社,2002:1–10.(CHENG Liangkui,FAN Jinglun,HAN Jun,et al.Soil and rock anchorage[M].Beijing:China Architecture and Building Press,2002:1–10.(in Chinese))
[3]程良奎,张培文,王帆.岩土锚固工程的若干力学概念问题[J].岩石力学与工程学报,2015,34(4):668–682.(CHENG Liangkui,ZHANG Peiwen,WANG Fan.Several mechanical conceptions for anchored structures in rock and soil[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(4):668–682.(in Chinese))
[4]FARMER I W.Stress distribution along a resin grouted rock anchor[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1975,12(11):347–351.
[5]蒋忠信.拉力型锚索锚固段剪应力分布的高斯曲线模式[J].岩土工程学报,2001,23(6):659–662.(JIANG Zhongxin.A Gauss curve model on shear stress along anchoring section of anchoring rope of extensional force type[J].Chinese Journal of Geotechnical Engineering,2001,23(6):659–662.(in Chinese))
[6]尤春安.全长粘结式锚杆的受力分析[J].岩石力学与工程学报,2000,19(3):334–338.(YOU Chun?an.Mechanical analysis on wholly grouted anchor[J].Chinese Journal of Rock Mechanics and Engineering,2000,19(3):334–338.(in Chinese))
[7]张季如,唐保付.锚杆荷载传递机制分析的双曲函数模型[J].岩土工程学报,2002,24(2):188–192.(ZHANG Jiru,TANG Baofu.Hyperbolic function model to analyze load transfer mechanism on bolts[J].Chinese Journal of Geotechnical Engineering,2002,24(2):188–192.(in Chinese))
[8]KUMAR S,KHAN M A.A shear-lag model for functionally graded adhesive anchors[J].International Journal of Adhesion and Adhesives,2016,68:317–325.
[9]ZHENG J J,DAI J G.analytical solution for the full-range pull-out behavior of FRP ground anchors[J].Construction and Building Materials,2014,58(10):129–137.
[10]ZHENG J J,DAI J G.Prediction of the nonlinear pull-out response of FRP ground anchors using an analytical transfer matrix method[J].Engineering Structures,2014,81:377–385.
[11]FREEMAN T J.The behaviour of fully-bonded rock bolts in the Kielder experimental tunnel[J].Tunnels and Tunneling International,1978,10(5):37–40.
[12]王明恕.全长锚固锚杆机制的探讨[J].煤炭学报,1983,3(1):40–47.(WANG Mingshu.Mechanism of full-column rock bolt[J].Journal of China Coal Society,1983,3(1):40–47.(in Chinese))
[13]CAI Y,ESAKI Y,JIANG Y J.An analytical model to predict axial load in grouted rock bolt for soft rock tunnelling[J].Tunnelling and Underground Space Technology,2004,19(6):607–618.
[14]谷拴成,丁潇.巷道顶板离层对锚杆载荷影响的弹性分析[J].煤炭科学技术,2012,40(6):33–36.(GU Shuancheng,DING Xiao.Elastic analysis on roadway roof bed separation affected to bolt loading[J].Coal Science and Technology,2012,40(6):33–36.(in Chinese))
[15]LI C C.Performance of D-bolts under static loading[J].Rock Mechanics and Rock Engineering,2012,45(2):183–192.
[16]LI C,STILLBORG B.Analytical models for rock bolts[J].International Journal of Rock Mechanics and Mining Sciences,1999,36(8):1 013–1 029.
[17]谷拴成,丁潇.岩体离层对锚固体荷载影响的弹塑性分析[J].岩土力学,2013,34(9):2 649–2 654.(GU Shuancheng,DING Xiao.Elastoplastic analysis of effect of bed separation on anchored mass loading in rock mass[J].Rock and Soil Mechanics,2013,34(9):2 649–2 654.(in Chinese))
[18]黄明华,周智,欧进萍.拉力型锚杆锚固段拉拔受力的非线性全历程分析[J].岩石力学与工程学报,2014,33(11):2 190–2 199.(HUANG Minghua,ZHOU Zhi,OU Jinping.Nonlinear full-range analysis of load transfer in fixed segment of tensile anchors[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(11):2 190–2 199.(in Chinese))
[19]丁潇.巷道围岩离层下锚杆荷载传递机制及支护设计研究[博士学位论文][D].西安:西安科技大学,2016.(DING Xiao.Research on bolt load transfer mechanism under bed separation effect and its support design[Ph.D.Thesis][D].Xi?an:Xi?an University of Science and Technology,2016.(in Chinese))
[20]黄明华.岩土锚杆拉拔荷载传递分析与FRP智能锚杆监测验证[博士学位论文][D].哈尔滨:哈尔滨工业大学,2014.(HUANG Minghua.Analysis on pullout load transfer mechanism of geotechnical anchor and its validating monitor with smart FRP anchor[Ph.D.Thesis][D].Harbin:Harbin Institute of Technology,2014.(in Chinese))