岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2013年
11期
3277-3283
,共7页
加筋土%加筋材料%动态松弛法%有限元法%梁单元%刚度效应
加觔土%加觔材料%動態鬆弛法%有限元法%樑單元%剛度效應
가근토%가근재료%동태송이법%유한원법%량단원%강도효응
reinforced sand%reinforced material%dynamic relaxation method%finite element method(FEM)%beam element%stiffness effect
为分析加筋材料的抗弯刚度对加筋性能的影响,加筋材料采用梁单元形式。基于动态松弛法,通过定义梁单元的刚度矩阵,求解内力矢量,随后定义虚拟质量密度而建立总质量矩阵,将加筋材料的梁单元有限元模型嵌入到已有的动态松弛法求解程序中。通过对简支梁的简单加载模拟验证了该梁单元模型的准确性能。随后,将该有限元模型与已有的动态松弛法计算程序结合(含砂土本构及弱面单元模型),对加筋砂土地基室内模型试验进行了数值模拟。将梁单元的模拟结果与杆单元(梁单元的特例)模拟结果进行了比较,并分别探讨了抗拉刚度和抗弯刚度对加筋砂土地基承载性能的影响。结果表明:抗拉刚度对承载能力的影响较小;抗弯刚度对承载力的影响程度与加筋材料的布置形式有关,特别是当加筋砂土中出现剪切带以后,其影响逐渐增大。因此,在分析加筋砂土结构的增强机制时,建议采用梁单元(具有一定的抗弯刚度)对加筋材料进行模拟。
為分析加觔材料的抗彎剛度對加觔性能的影響,加觔材料採用樑單元形式。基于動態鬆弛法,通過定義樑單元的剛度矩陣,求解內力矢量,隨後定義虛擬質量密度而建立總質量矩陣,將加觔材料的樑單元有限元模型嵌入到已有的動態鬆弛法求解程序中。通過對簡支樑的簡單加載模擬驗證瞭該樑單元模型的準確性能。隨後,將該有限元模型與已有的動態鬆弛法計算程序結閤(含砂土本構及弱麵單元模型),對加觔砂土地基室內模型試驗進行瞭數值模擬。將樑單元的模擬結果與桿單元(樑單元的特例)模擬結果進行瞭比較,併分彆探討瞭抗拉剛度和抗彎剛度對加觔砂土地基承載性能的影響。結果錶明:抗拉剛度對承載能力的影響較小;抗彎剛度對承載力的影響程度與加觔材料的佈置形式有關,特彆是噹加觔砂土中齣現剪切帶以後,其影響逐漸增大。因此,在分析加觔砂土結構的增彊機製時,建議採用樑單元(具有一定的抗彎剛度)對加觔材料進行模擬。
위분석가근재료적항만강도대가근성능적영향,가근재료채용량단원형식。기우동태송이법,통과정의량단원적강도구진,구해내력시량,수후정의허의질량밀도이건립총질량구진,장가근재료적량단원유한원모형감입도이유적동태송이법구해정서중。통과대간지량적간단가재모의험증료해량단원모형적준학성능。수후,장해유한원모형여이유적동태송이법계산정서결합(함사토본구급약면단원모형),대가근사토지기실내모형시험진행료수치모의。장량단원적모의결과여간단원(량단원적특례)모의결과진행료비교,병분별탐토료항랍강도화항만강도대가근사토지기승재성능적영향。결과표명:항랍강도대승재능력적영향교소;항만강도대승재력적영향정도여가근재료적포치형식유관,특별시당가근사토중출현전절대이후,기영향축점증대。인차,재분석가근사토결구적증강궤제시,건의채용량단원(구유일정적항만강도)대가근재료진행모의。
To analyze the influence of bending stiffness of reinforcement on the bearing capacity of reinforced soil structures, the beam element form is applied to modeling for reinforcement. Based on the dynamic relaxation (DR) method, the finite element model of beam element simulating reinforcement is presented. Firstly, the beam element stiffness matrix is constructed and the solution to internal force vector is obtained. Then, the fictitious mass density is defined just for numerical purposes and a mass matrix is established. The beam model is embedded in the existing dynamic relaxation calculation program. To validate the performance and accuracy of the beam element model , the loading simulation of simple beam is conducted. Subsequently model, the numerical study for the reinforced sandy ground physical model test is carried out by combining the beam element model and the DR calculation program (including the sand constitutive and the interface models). The comparison of simulation results between the beam element model and bar element model are conducted. The influences of tensile stiffness and bending stiffness on the bearing capacities of reinforced sand foundation are discussed respectively. The simulation results show that the tensile stiffness has little effect on the bearing capacity of the reinforced sand foundation. The influence of bending stiffness on bearing capacity is related to the reinforcement layout;especially when the shear band occurs in the reinforced sand structures, the impact will increase. Thus, to analyze the reinforced mechanism of reinforced sand structures, the beam element is recommended (with bending stiffness) in the simulation procedure.