在拉剪组合荷载作用下自锁锚杆锚固性能试验研究
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摘要
本文是对自锁锚杆在拉伸和剪切荷载共同作用下的锚固机理进行研究。试验选用两种直径(即φ16、φ20)和四种加载角度(即0°、30°、45°、60°)，共24根试件。观察锚杆整个受力和破坏过程，测得锚杆轴向、横向变形和极限破坏荷载；通过对荷载—变形曲线的分析锚杆在拉剪组合荷载作用下的变形规律；选用三种方程(直线方程、三直线方程以及椭圆方程)对锚杆的极限承载力进行描述和比较；分析混凝土和钢筋的破坏模式；并在此基础上利用有限元方法对此试验进行数值模拟，将计算结果与试验结果做比较；最后采用神经网络的方法对自锁锚杆的极限承载力预测进行了尝试，对预测值和试验值进行比较。得出以下一些研究成果：
(1) 自锁锚杆在拉剪组合荷载作用下的荷载—变形曲线分析表明，锚杆钢筋的变形大致上可以分为两个阶段，前一阶段基本满足线性规律，后一阶段锚杆每荷载步的变形较大，非线性特征明显；无论是横向变形还是轴向变形，当加载角度为45°时，非线性特征最显著；随着加载角度的增加，两种锚杆的极限承载力均增加，直径为20mm的锚杆增加幅度要大；采用a=2的椭圆方程能较好地拟合本文试验中得到的锚杆极限承载力，为锚杆设计提供了理论依据。
(2) 在拉剪组合荷载作用下，锚杆的失效包括两部分，一部分是混凝土的斜锥体破坏，一部分是锚杆钢筋的断裂；当加载角度为30°时，混凝土体的破坏形状最接近正锥体，且锥顶深度最大，锥底面积最小；随着加载角度的增大，锥顶深度变浅，锥底面积最大。锚杆断裂后，断口形状具有如下规律：加载角度为30°的锚杆断口为杯口状，加载角度为45°的断口受拉部位为接近平面，受压区接近30°的斜面，加载角度为60°的锚杆断口则为接近45°的斜面。
(3) 采用有限元数值分析方法，分析了锚杆在拉剪组合荷载作用下的极限承载力，结果表明，数值计算结果与实测结果具有可比性。受压区混凝土应力表明，混凝土的破坏面呈扇形弧状分布。这与实际测试结果是一致的。
(4) 运用现代信息技术中神经网络方法对拉剪组合荷载作用下锚杆的极限承载力进行了预测。通过预测值与实验值的比较表明，该方法的预测结果具有较高的精度。利用训练好的神经网络，进行指定的输出，对锚杆极限承载力的影响因素进行了探讨。
The anchorage mechanism of the locking anchor under tension together shear loads is studied in the paper. Twenty-four specimens which differ in two kind of diameters (F 16,F20) and four kinds of load angles (00,30?45?600), are selected in the experiment. The load-deforming curve is got through the experiment of the each single anchor under tension together shear loads, then the axial and transverse deformations and ultimate bearing capacity of the anchor can be got too. The deforming rule of the anchor under the tension and shear loads is found by analysis of the load-deforming curve. Three sorts of functions (straight-line function, trilinear function and elliptical function) are used to illustrate and compare the ultimate bearing capacity of anchor; analyzing the demolish mode of the concrete and the locking anchor. Moreover, numerical simulate on this experimentation with finite element method is conducted. The experiment and numerical results are compared with each other in succession. In the end, the
ultimate bearing capacity of the locking anchor is forecasted with artificial neural network (ANN) method and the forecasting value is compared with the experiment value. The following achievements are obtained:
(1) The load- deformation curve of the locking anchor under tension together shear loads shows that the deformation of the anchor can be mainly divided into two stages: in the first stage it satisfies the linear law; in the latter, there is a big deformation per load pace, and behaves as nonlinear characteristic in evidence. No matter it is axial deformation or transverse one, it behaves the most nonlinear when the load angle is 45 degrees. The ultimate bearing capacity of two kinds of anchor increase with the enhancement of the load angle, and the anchor with diameter 20 millimeters increase more obviously than the other one. The elliptical function with the parameter a equals 2 can fit the ultimate bearing capacity in the experiment very well, which can provide a theory basis for the design of the anchor.
(2) Under the tension together shear loads the invalidation of the anchor consists of two parts: one is declined cone failure of the concrete, the other is the failure of the anchor;
When the load angle is 30 degrees, the form of the failure is almost the cone one, which
induces the biggest depth of the cone peak and smallest area of the cone bottom. With the increase of the load angle, the cone peak become lower in depth and the cone bottom becomes smaller in area. After the failure of the anchor, the fracture surfaces have the following results: it is a rim of a cup when the load angle is 30 degrees, nearly a plane in the drew part and near 30 degrees inclined plane in the compression area when the load angle is 45 degrees and near 45 degrees inclined plane in the fracture when the load angle is 60 degrees.
(3) The ultimate bearing capacity of anchor under tension together shear loads is analyzed using the finite element method in the paper. The result shows that the numerical results are comparable with the experimentation ones. The stress in concrete compressive zone shows that the fracture surfaces of concrete performs sector-arc distribution which is consistent with the experiment results.
(4) The ultimate bearing capacity of anchor under tension together shear loads is forecasted by neural network method in the modem information technique. According to the compare between the forecasting value and the experiment one, we are convinced that this method holds a high accuracy. The influence factors of the ultimate bearing capacity of anchor are studied using the trained neural network together with the special output.
(1) 自锁锚杆在拉剪组合荷载作用下的荷载—变形曲线分析表明，锚杆钢筋的变形大致上可以分为两个阶段，前一阶段基本满足线性规律，后一阶段锚杆每荷载步的变形较大，非线性特征明显；无论是横向变形还是轴向变形，当加载角度为45°时，非线性特征最显著；随着加载角度的增加，两种锚杆的极限承载力均增加，直径为20mm的锚杆增加幅度要大；采用a=2的椭圆方程能较好地拟合本文试验中得到的锚杆极限承载力，为锚杆设计提供了理论依据。
(2) 在拉剪组合荷载作用下，锚杆的失效包括两部分，一部分是混凝土的斜锥体破坏，一部分是锚杆钢筋的断裂；当加载角度为30°时，混凝土体的破坏形状最接近正锥体，且锥顶深度最大，锥底面积最小；随着加载角度的增大，锥顶深度变浅，锥底面积最大。锚杆断裂后，断口形状具有如下规律：加载角度为30°的锚杆断口为杯口状，加载角度为45°的断口受拉部位为接近平面，受压区接近30°的斜面，加载角度为60°的锚杆断口则为接近45°的斜面。
(3) 采用有限元数值分析方法，分析了锚杆在拉剪组合荷载作用下的极限承载力，结果表明，数值计算结果与实测结果具有可比性。受压区混凝土应力表明，混凝土的破坏面呈扇形弧状分布。这与实际测试结果是一致的。
(4) 运用现代信息技术中神经网络方法对拉剪组合荷载作用下锚杆的极限承载力进行了预测。通过预测值与实验值的比较表明，该方法的预测结果具有较高的精度。利用训练好的神经网络，进行指定的输出，对锚杆极限承载力的影响因素进行了探讨。
The anchorage mechanism of the locking anchor under tension together shear loads is studied in the paper. Twenty-four specimens which differ in two kind of diameters (F 16,F20) and four kinds of load angles (00,30?45?600), are selected in the experiment. The load-deforming curve is got through the experiment of the each single anchor under tension together shear loads, then the axial and transverse deformations and ultimate bearing capacity of the anchor can be got too. The deforming rule of the anchor under the tension and shear loads is found by analysis of the load-deforming curve. Three sorts of functions (straight-line function, trilinear function and elliptical function) are used to illustrate and compare the ultimate bearing capacity of anchor; analyzing the demolish mode of the concrete and the locking anchor. Moreover, numerical simulate on this experimentation with finite element method is conducted. The experiment and numerical results are compared with each other in succession. In the end, the
ultimate bearing capacity of the locking anchor is forecasted with artificial neural network (ANN) method and the forecasting value is compared with the experiment value. The following achievements are obtained:
(1) The load- deformation curve of the locking anchor under tension together shear loads shows that the deformation of the anchor can be mainly divided into two stages: in the first stage it satisfies the linear law; in the latter, there is a big deformation per load pace, and behaves as nonlinear characteristic in evidence. No matter it is axial deformation or transverse one, it behaves the most nonlinear when the load angle is 45 degrees. The ultimate bearing capacity of two kinds of anchor increase with the enhancement of the load angle, and the anchor with diameter 20 millimeters increase more obviously than the other one. The elliptical function with the parameter a equals 2 can fit the ultimate bearing capacity in the experiment very well, which can provide a theory basis for the design of the anchor.
(2) Under the tension together shear loads the invalidation of the anchor consists of two parts: one is declined cone failure of the concrete, the other is the failure of the anchor;
When the load angle is 30 degrees, the form of the failure is almost the cone one, which
induces the biggest depth of the cone peak and smallest area of the cone bottom. With the increase of the load angle, the cone peak become lower in depth and the cone bottom becomes smaller in area. After the failure of the anchor, the fracture surfaces have the following results: it is a rim of a cup when the load angle is 30 degrees, nearly a plane in the drew part and near 30 degrees inclined plane in the compression area when the load angle is 45 degrees and near 45 degrees inclined plane in the fracture when the load angle is 60 degrees.
(3) The ultimate bearing capacity of anchor under tension together shear loads is analyzed using the finite element method in the paper. The result shows that the numerical results are comparable with the experimentation ones. The stress in concrete compressive zone shows that the fracture surfaces of concrete performs sector-arc distribution which is consistent with the experiment results.
(4) The ultimate bearing capacity of anchor under tension together shear loads is forecasted by neural network method in the modem information technique. According to the compare between the forecasting value and the experiment one, we are convinced that this method holds a high accuracy. The influence factors of the ultimate bearing capacity of anchor are studied using the trained neural network together with the special output.
引文
[1] 高作平，陈明祥．混凝土结构粘结加固技术新发展．水利水电出版社，1999
[2] 朱伯龙、刘祖华著．建筑改造工程学．上海：同济大学出版社，1998
[3] 王永维．我国建筑物鉴定与加固改造技术现状与展望．第五届全国建筑物鉴定与加固技术会议论文集上册，2002
[4] 陈锦华．植筋锚固技术及造价分析．价值工程，2001(4)
[5] 陆士良，汤雷等著．锚杆锚固力与锚固技术．北京：北京煤炭工业出，1998
[6] 程良奎，张作媚，杨志银．岩土加固使用技术．北京：地震出版社 1994
[7] 刘辉等．植筋技术应用研究浅议．建筑技术开发，2003(12)
[8] 陈炜新．钢筋混凝土结构植筋锚固新技术．西部探矿工程，2003(2)
[9] 李钟彬，贾壮普，姜波．HIT—HY150植筋锚固技术．建筑结构，1998(12)
[10] T．H．汉纳(英国)编，张清，张弥等著．锚固技术在岩土工程中的应用．北京：中国建筑工业出版社，1987
[11] 张志强．锚栓在结构工程中的应用问题．建筑技术开发，2000(3)
[12] 徐有邻．钢筋混凝土粘结锚固性能的试验研究．建筑结构学报，1994(3)
[13] 程良奎．我国岩土锚固技术的现状与发展．北京：地震出版社，1991
[14] 李北星．ICG无机粘结灌注材料技术研究报告．武汉：武汉大学材料力学教研室，2000
[15] 李北星，陈明祥，高作平．无机快速锚固灌浆材料的性能和应用研究．水利水电技术，2003(6)
[16] Ronald A. Cook, Jacob Kunz, Werner Fuchs, Robert C. Konz. "Behavior and Design Of Single Adhesive Anchors under Tensile Load in Uncracked Concrete". ACI structural Journal,1998. V. 95. No. 1
[17] Cook. R. A, "Behaviour of Chemically Bonded Anchors", Journal of Structural Engineering, American Society of Civil Engineers, 1993. V. 119. No. 9
[18] R. A. Cook, G. T. Doerr, R. E. Klingner, "BonD Stress Model for Design of Adhesive Anchors", ACI Structural, 1993. V. 90. No. 5
[19] 刘新红．在横向荷载作用下自锁锚杆抗剪性能试验研究．武汉：武汉大学硕士学
位论文，2003
[20] 何勇．混凝土结构化学粘结锚杆锚固性能的研究．武汉：武汉大学硕士学位论文，2001
[21] 宋建波，张倬元，刘汉超．用Hook-Brown经验强度准则估算岩石锚杆容许抗拔力．地质灾害与环境保护，2001(12)
[22] 王勖成、邵敏著．有限元法基本原理和数值方法．北京：清华大学出版社，1997
[23] 钱伟长，叶开源．弹性力学．北京：科学出版社，1998
[24] 蒋友谅著．非线性有限元法．北京：北京理工大学出版社，1988
[25] 康清梁，宋玉普．钢筋混凝土有限元分析．北京：中国水利水电出版社，1996
[26] 江见鲸．关于钢筋混凝土数值分析中的本构关系．力学进展，1994(1)
[27] 雷林源．基于神经网络的结构优化与损伤检测．北京：科学出版社，2002
[28] 潘冬子．小波分析机器在基桩完整性检测中的应用研究．武汉：中国科学院武汉岩土力学研究所，2004-5-14
[29] 王成华，张薇．人工神经网络在桩基础中的应用综述．岩土力学，2002(2)
[30] 张定会，戴曙光．混合故障诊断专家系统．模式识别与人工智能，2000(3)
[31] 李学桥，马莉．神经网络·工程应用．重庆：重庆大学出版社，1996
[32] 张际先，宓霞．神经网络及其在工程中的应用．北京：机械工业出版社，1996
[33] 陈明祥．弹塑性力学．2003
[34] 蓝宗建．混凝土结构．南京：东南大学出版社，1999
[2] 朱伯龙、刘祖华著．建筑改造工程学．上海：同济大学出版社，1998
[3] 王永维．我国建筑物鉴定与加固改造技术现状与展望．第五届全国建筑物鉴定与加固技术会议论文集上册，2002
[4] 陈锦华．植筋锚固技术及造价分析．价值工程，2001(4)
[5] 陆士良，汤雷等著．锚杆锚固力与锚固技术．北京：北京煤炭工业出，1998
[6] 程良奎，张作媚，杨志银．岩土加固使用技术．北京：地震出版社 1994
[7] 刘辉等．植筋技术应用研究浅议．建筑技术开发，2003(12)
[8] 陈炜新．钢筋混凝土结构植筋锚固新技术．西部探矿工程，2003(2)
[9] 李钟彬，贾壮普，姜波．HIT—HY150植筋锚固技术．建筑结构，1998(12)
[10] T．H．汉纳(英国)编，张清，张弥等著．锚固技术在岩土工程中的应用．北京：中国建筑工业出版社，1987
[11] 张志强．锚栓在结构工程中的应用问题．建筑技术开发，2000(3)
[12] 徐有邻．钢筋混凝土粘结锚固性能的试验研究．建筑结构学报，1994(3)
[13] 程良奎．我国岩土锚固技术的现状与发展．北京：地震出版社，1991
[14] 李北星．ICG无机粘结灌注材料技术研究报告．武汉：武汉大学材料力学教研室，2000
[15] 李北星，陈明祥，高作平．无机快速锚固灌浆材料的性能和应用研究．水利水电技术，2003(6)
[16] Ronald A. Cook, Jacob Kunz, Werner Fuchs, Robert C. Konz. "Behavior and Design Of Single Adhesive Anchors under Tensile Load in Uncracked Concrete". ACI structural Journal,1998. V. 95. No. 1
[17] Cook. R. A, "Behaviour of Chemically Bonded Anchors", Journal of Structural Engineering, American Society of Civil Engineers, 1993. V. 119. No. 9
[18] R. A. Cook, G. T. Doerr, R. E. Klingner, "BonD Stress Model for Design of Adhesive Anchors", ACI Structural, 1993. V. 90. No. 5
[19] 刘新红．在横向荷载作用下自锁锚杆抗剪性能试验研究．武汉：武汉大学硕士学
位论文，2003
[20] 何勇．混凝土结构化学粘结锚杆锚固性能的研究．武汉：武汉大学硕士学位论文，2001
[21] 宋建波，张倬元，刘汉超．用Hook-Brown经验强度准则估算岩石锚杆容许抗拔力．地质灾害与环境保护，2001(12)
[22] 王勖成、邵敏著．有限元法基本原理和数值方法．北京：清华大学出版社，1997
[23] 钱伟长，叶开源．弹性力学．北京：科学出版社，1998
[24] 蒋友谅著．非线性有限元法．北京：北京理工大学出版社，1988
[25] 康清梁，宋玉普．钢筋混凝土有限元分析．北京：中国水利水电出版社，1996
[26] 江见鲸．关于钢筋混凝土数值分析中的本构关系．力学进展，1994(1)
[27] 雷林源．基于神经网络的结构优化与损伤检测．北京：科学出版社，2002
[28] 潘冬子．小波分析机器在基桩完整性检测中的应用研究．武汉：中国科学院武汉岩土力学研究所，2004-5-14
[29] 王成华，张薇．人工神经网络在桩基础中的应用综述．岩土力学，2002(2)
[30] 张定会，戴曙光．混合故障诊断专家系统．模式识别与人工智能，2000(3)
[31] 李学桥，马莉．神经网络·工程应用．重庆：重庆大学出版社，1996
[32] 张际先，宓霞．神经网络及其在工程中的应用．北京：机械工业出版社，1996
[33] 陈明祥．弹塑性力学．2003
[34] 蓝宗建．混凝土结构．南京：东南大学出版社，1999