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考虑土层锚索埋深及界面相对位移的抗拔性状研究

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考虑土层锚索埋深及锚固体-土体界面相对位移关系,提出了一种利用室内界面剪切试验结果计算锚索抗拔荷载-位移关系方法.该法首先根据锚索埋深确定室内界面剪切试验法向压力,并基于自制界面剪切试验装置得到界面剪应力-位移关系(r-w)拟合公式;然后,基于锚固体弹性变形假设及土体变形Mindlin解,建立了锚固体-土体界面相对位移计算公式;最后,采用单元法,考虑r-w拟合结果及界面相对位移关系,建立了锚索抗拔荷载-位移关系计算方法,得到的锚索抗拔荷载-位移计算曲线与实测结果吻合度更高.随拉拔荷载提高,锚固段界面相对位移和锚固段轴力均表现出由近及远逐渐发展特点,且相对位移表现出明显"下凹"特点,锚固段轴力表现明显的"上凸"特点.此外,随加载量提高,锚固段侧摩阻力大小逐渐提高,侧摩阻力作用范围逐渐扩大,并受锚固段埋深影响,埋深较大锚固段侧摩阻力较埋深较小情况小,存在明显的滞后现象.
Pullout Mechanism of Soil Anchor Considering Embedded Depth and Relative Displacement Relationship at Interface
Based on the laboratory interface shear test results,a method of estimating the pullout load-displacement is proposed considering the embedded depth and the relative displacement relationship of the grout-soil interface.Firstly,the normal stress for the interface shear test can been obtained according to the embedded depth of the soil anchor.Then the fitting formulas were obtained by the laboratory interface shear tests and the curve fitting method.Secondly,based on the elastic deformation as-sumption of the anchoring segment and the Mindlin solution of the soil deformation,the relative displacement formula is pro-posed for the anchoring segment and the soil of interface.Finally,according to fitting curves of the shear test and the interface relative deformation,a formula for the pullout load with the displacement is established.The results indicate that curves of the anchor pullout load-displacement are more consistent with curves by the laboratory shear test than the other theoretical meth-ods.The axial force and the relative displacement of the anchoring segment interface raised from the top to the end with the im-provement of the pullout load of the soil anchor.The relative displacement curves show an obvious concave-characteristics,while the axial force curves of the anchoring segment show the strong convex-characteristics.In addition,with the increase of the pullout load,the friction resistance increases gradually,and range of friction resistance is gradually expanded.The greater the embedded depth,the smaller the resistance.The friction resistance of the anchoring segment has an obvious hysteresis phe-nomenon for the embedded depth of the soil anchor.

Soil AnchorPullout MechanicalFriction ResistanceRelative DisplacementMindlin Solution

陈小巍、朱浩锋、刘庭

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湖南省水文地质环境地质调查监测所,湖南株洲 412008

土层锚索 抗拔性状 侧摩阻力 相对位移 Mindlin解

2024

土工基础
湖北省土木建筑学会,中国科学院武汉岩土力学研究所,武汉市土木建筑学会

土工基础

影响因子:0.238
ISSN:1004-3152
年,卷(期):2024.38(6)