岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2013年
7期
2043-2050
,共8页
胶结岩土材料%破损%本构模型%微观理论%离散元法
膠結巖土材料%破損%本構模型%微觀理論%離散元法
효결암토재료%파손%본구모형%미관이론%리산원법
bonded geomaterials%degradation%constitutive model%microscopic theory%DEM
采用离散元法（DEM）研究胶结岩土材料在不同加载条件下的结构破损规律。首先，基于微观力学理论，考虑胶结岩土材料颗粒间胶结特性，给出表征结构性损伤的破损参数式。该式具有微观物理意义，但不能直接用于建立宏观本构模型。其次，采用二维离散元源程序NS2D模拟等向压缩、等应力比压缩以及双轴压缩试验，分析破损参数在不同加载条件下随宏观力学变量（体积应变和剪应变）的演变规律。最后，根据模拟结果提出破损参数数学表达式，其为大主应变的函数。研究结果表明：胶结强度、应力比以及围压均在一定程度上影响了数值试样的结构破损规律。在等向压缩和等应力比压缩试验中，容易用函数式描述数值试样破损参数随体积应变或偏应变的演变规律；而在双轴压缩条件下，由于数值试样有剪胀特性，破损参数随体积应变的演变规律则不易描述。建议的破损参数数学表达式能够较好地描述数值试样在不同加载条件下结构破损规律。
採用離散元法（DEM）研究膠結巖土材料在不同加載條件下的結構破損規律。首先，基于微觀力學理論，攷慮膠結巖土材料顆粒間膠結特性，給齣錶徵結構性損傷的破損參數式。該式具有微觀物理意義，但不能直接用于建立宏觀本構模型。其次，採用二維離散元源程序NS2D模擬等嚮壓縮、等應力比壓縮以及雙軸壓縮試驗，分析破損參數在不同加載條件下隨宏觀力學變量（體積應變和剪應變）的縯變規律。最後，根據模擬結果提齣破損參數數學錶達式，其為大主應變的函數。研究結果錶明：膠結彊度、應力比以及圍壓均在一定程度上影響瞭數值試樣的結構破損規律。在等嚮壓縮和等應力比壓縮試驗中，容易用函數式描述數值試樣破損參數隨體積應變或偏應變的縯變規律；而在雙軸壓縮條件下，由于數值試樣有剪脹特性，破損參數隨體積應變的縯變規律則不易描述。建議的破損參數數學錶達式能夠較好地描述數值試樣在不同加載條件下結構破損規律。
채용리산원법（DEM）연구효결암토재료재불동가재조건하적결구파손규률。수선，기우미관역학이론，고필효결암토재료과립간효결특성，급출표정결구성손상적파손삼수식。해식구유미관물리의의，단불능직접용우건립굉관본구모형。기차，채용이유리산원원정서NS2D모의등향압축、등응력비압축이급쌍축압축시험，분석파손삼수재불동가재조건하수굉관역학변량（체적응변화전응변）적연변규률。최후，근거모의결과제출파손삼수수학표체식，기위대주응변적함수。연구결과표명：효결강도、응력비이급위압균재일정정도상영향료수치시양적결구파손규률。재등향압축화등응력비압축시험중，용역용함수식묘술수치시양파손삼수수체적응변혹편응변적연변규률；이재쌍축압축조건하，유우수치시양유전창특성，파손삼수수체적응변적연변규률칙불역묘술。건의적파손삼수수학표체식능구교호지묘술수치시양재불동가재조건하결구파손규률。
The degradation evolution of the bonded geomaterials under different loading conditions is investigated by using distinct element method (DEM). First, considering the bonding behavior at contacts between bonded geomaterials, an equation of degradation parameter, which is used to describe the degradation process in bonded geomaterials, is established based on the micromechanics theory. The equation has microscopic physical significance, which cannot be directly used to establish macroscopic constitutive model. Second, a series of isotropic, constant stress ratio and biaxial compression tests are performed on the numerical specimens by using a two-dimensional DEM code, NS2D; and the evolution of the degradation variable varying with macro variables, i.e. volumetric and shear strains, is investigated under the three loading conditions. Finally, a simple evolution equation for the degradation parameter is proposed; and it is a function of the major principal strain. It is shown that three variables, i.e. bond strength, constant stress ratio, and confining pressure, can influence the degradation evolution of the numerical specimens to a certain extent. The evolution of the parameter varying with the volumetric or deviatoric strains can be easily described by functions in the isotropic and constant stress ratio compression tests. The evolution of the parameter varying with the volumetric strain cannot be easily described due to the dilatancy in the specimens under biaxial compression tests. The equation proposed for the degradation parameter can well describe the degradation evolution observed in the three loading conditions.
