塌陷区上覆加筋路基力学行为演化与变形机理细观研究OA北大核心CSTPCD
Mesoscopic study on mechanical behavior evolution and deformation mechanism of overlying reinforced subgrade in subsidence area
为深入揭示塌陷区上覆加筋路基力学行为演化与变形机理,本文基于室内试验建立塌陷区上覆加筋路基离散元数值分析模型,从细观层面分析不同筋材长度、塌陷区宽度、路基高度条件下颗粒间接触力链分布、颗粒间相对位移、筋材弯曲变形与拉力、土拱比等变化规律,进而探究筋材长度、塌陷区宽度、路基高度对加筋路基力学行为与变形机理的影响规律.研究结果表明:合理的加筋长度能够使筋材有效承担上部路基荷载并限制路基填料颗粒间的相对位移;本研究中当筋材长度L=500 mm时,限制路基填料颗粒间相对位移的效果最佳,此时,筋材拉力达到最大值,筋材的弯曲变形达到最小值,颗粒间接触力链形状表现为完整拱形;在锚固比相同的条件下,塌陷区宽度越大,土拱效应的发挥程度就越低,土拱比就越小,颗粒间接触力链形状由完整拱形演变为2条未闭合的斜边,随着塌陷区宽度的增加,路基变形范围和筋材变形逐渐增加,加筋效果逐渐减弱;随着路基高度的增加,能够有效限制土拱效应的退化并使土拱效应得到充分发挥,颗粒间接触力链形状由2条和路基底部具有一定夹角的斜边演变为完整拱形,筋材拉力逐渐增大,筋材水平与竖向位移均逐渐减小,路基变形范围形状由矩形变为环状椭圆形且宽度基本不变.
In order to reveal the mechanical behavior evolution and deformation mechanism of reinforced subgrade in subsidence area,a discrete element model of reinforced subgrade in subsidence area was established based on laboratory tests.From the mesoscopic level,the distribution of contact force chain between particles,relative displacement between particles,bending deformation and tension of reinforcement,and soil arch ratio under different reinforcement length,subsidence width and subgrade height were analyzed.The influence of reinforcement length,subsidence width and subgrade height on the mechanical behavior and deformation mechanism of reinforced subgrade was explored.The results show that a reasonable length of reinforcement material can make the reinforcement effectively bear the load of the upper subgrade and limit the relative displacement between the subgrade fillings.In this study,the effect of limiting the relative displacement of subgrade filling is the best when the length of reinforcement L=500 mm.Moreover,the tension of the reinforcement reaches the maximum value,the bending deformation of the reinforcement reaches the minimum value,and the shape of the particle contact force chain is shown as a complete arch.Under the condition of the same anchoring ratio,the larger the subsidence width,the lower the degree of soil arching effect,the smaller the soil arching ratio,and the shape of the particle contact force chain evolves from a complete arch to two unclosed bevels.With the increase of the subsidence width,the deformation range of the subgrade and the deformation of the reinforcement gradually increase,and the reinforcement effect gradually weakens.With the increase of subgrade height,the degradation of soil arching can be effectively restricted and soil arching effect is fully shown.The shape of the contact force chain among the particles evolves from two inclined edges with a certain angle to the bottom of the subgrade to a complete arch.The tensile forces along the reinforcement increase gradually,while the horizontal and vertical displacements of the reinforcement decrease gradually.Additionally,the shape of the subgrade deformation range changes from rectangular to annular ellipse with the width almost unchanged.
王志杰;高古顺;杨广庆;熊保林;秦岩;孟猛
石家庄铁道大学省部共建交通工程结构力学行为与系统安全国家重点实验室,河北石家庄,050043||土工合成材料应用河北省工程研究中心,河北石家庄,050043||石家庄铁道大学土木工程学院,河北石家庄,050043石家庄铁道大学省部共建交通工程结构力学行为与系统安全国家重点实验室,河北石家庄,050043||石家庄铁道大学土木工程学院,河北石家庄,050043河北供水有限责任公司,河北石家庄,050011
交通运输
加筋路基局部塌陷区土工织物力学行为变形机理离散元模拟
reinforced subgradelocal subsidence areageotextilemechanical behaviordeformation mechanismdiscrete element modeling
《中南大学学报（自然科学版）》 2024 (004)
1523-1536 / 14
国家重点研发计划项目(2022YFE0104600);国家自然科学基金资助项目(51709175)(Project(2022YFE104600)supported by the National Key R&D Program of China;Project(51709175)supported by the National Natural Science Foundation of China)
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