岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2014年
10期
2807-2814,2830
,共9页
边界面塑性模型%初始各向异性%变换应力法%循环载荷%饱和黏土
邊界麵塑性模型%初始各嚮異性%變換應力法%循環載荷%飽和黏土
변계면소성모형%초시각향이성%변환응역법%순배재하%포화점토
bounding surface plasticity model%initial anisotropy%transformed stress method%cyclic loading%saturated clay
天然土体的初始各向异性通常可对其后继循环特性产生显著影响。现有考虑循环载荷作用的土体弹塑性模型,往往采用类似修正剑桥模型的椭圆形屈服面,已有研究表明,该椭圆形屈服面因其拉伸弹性区域偏大,针对天然 K0固结状态的土体,其计算精度较差。基于新近提出的广义各向同性硬化准则,在边界面方程中引入初始各向异性张量,并采用空间滑动面破坏准则(SMP)的变换应力法,建立了能考虑饱和黏土初始各向异性的循环边界面塑性模型。分别针对等压和偏压固结的饱和黏土静、动三轴试验进行模拟,结果表明,该模型能合理反映土体的初始各向异性及其后继循环动力特性。
天然土體的初始各嚮異性通常可對其後繼循環特性產生顯著影響。現有攷慮循環載荷作用的土體彈塑性模型,往往採用類似脩正劍橋模型的橢圓形屈服麵,已有研究錶明,該橢圓形屈服麵因其拉伸彈性區域偏大,針對天然 K0固結狀態的土體,其計算精度較差。基于新近提齣的廣義各嚮同性硬化準則,在邊界麵方程中引入初始各嚮異性張量,併採用空間滑動麵破壞準則(SMP)的變換應力法,建立瞭能攷慮飽和黏土初始各嚮異性的循環邊界麵塑性模型。分彆針對等壓和偏壓固結的飽和黏土靜、動三軸試驗進行模擬,結果錶明,該模型能閤理反映土體的初始各嚮異性及其後繼循環動力特性。
천연토체적초시각향이성통상가대기후계순배특성산생현저영향。현유고필순배재하작용적토체탄소성모형,왕왕채용유사수정검교모형적타원형굴복면,이유연구표명,해타원형굴복면인기랍신탄성구역편대,침대천연 K0고결상태적토체,기계산정도교차。기우신근제출적엄의각향동성경화준칙,재변계면방정중인입초시각향이성장량,병채용공간활동면파배준칙(SMP)적변환응역법,건립료능고필포화점토초시각향이성적순배변계면소성모형。분별침대등압화편압고결적포화점토정、동삼축시험진행모의,결과표명,해모형능합리반영토체적초시각향이성급기후계순배동력특성。
The initial anisotropy of natural soft clay tends to have a significant influence on its subsequent cyclic behaviors. The current elastoplastic constitutive models for cyclic behaviors of saturated clay always adopt an elliptic yield surface similar to the one in the modified Cam-clay model. However, studies have demonstrated that these kinds of models which adopt an elliptic yield surface are not suitable for predicting the characteristics of K0-consolidated soils under the extension state, due to its over-predicted elastic region. In this paper, within the framework of the generalized isotropic hardening rule, by introducing the initial anisotropic tensor to the formation of the bounding surface and combining with the transformed stress tensors which are based on the spatially mobilized plane (SMP) yield criterion, a new bounding surface plasticity model for saturated clay with initial anisotropy is proposed. The predicted results by the model for the monotonic and cyclic triaxial tests on both isotropically and anisotropically consolidated clays demonstrate that the bounding surface model can reasonably describe the initial anisotropy and the subsequent cyclic behaviors of saturated clay.