岩土力学
巖土力學
암토역학
Rock and Soil Mechanics
2015年
11期
3307-3314
,共8页
四参数随机生长法%土体细观结构%格子Boltzmann方法%渗流场%数值模拟
四參數隨機生長法%土體細觀結構%格子Boltzmann方法%滲流場%數值模擬
사삼수수궤생장법%토체세관결구%격자Boltzmann방법%삼류장%수치모의
quartet structure generation set (QSGS)%mesoscopic structure of soil%lattice Boltzmann method(LBM)%seepage field%numerical simulation
真实土体的细观结构由许多个大小不一的土颗粒团组成,传统四参数随机生长法(QSGS)构建的土体结构土颗粒团比较均匀,与实际情况存在较大的差异。为弥补这一缺陷,考虑土体孔隙率及自相关函数的影响,对传统的四参数随机生长法进行改进,实现了更接近于真实土体的细观结构重构。在此基础上基于格子Boltzmann方法,采用D2Q9模型,通过设置模型入口、出口边界为非平衡态外推格式,左右边界及土颗粒边界为标准反弹格式的边界条件,建立了模拟重构土体细观渗流场的二维模型。同时,针对一算例编制了相应的计算程序,研究了恒定流速入渗情况下重构土体的细观渗流场。研究表明:土体的渗流方向优先选择连通性较好孔隙所形成的通道,流速受控于通道整体连通性的优劣。整体贯通型的通道流动速度较快,部分连通的孔隙中其流动速度相对较慢。即使局部孔隙空间较大,其渗流速度仍取决于是否位于贯通型通道上。
真實土體的細觀結構由許多箇大小不一的土顆粒糰組成,傳統四參數隨機生長法(QSGS)構建的土體結構土顆粒糰比較均勻,與實際情況存在較大的差異。為瀰補這一缺陷,攷慮土體孔隙率及自相關函數的影響,對傳統的四參數隨機生長法進行改進,實現瞭更接近于真實土體的細觀結構重構。在此基礎上基于格子Boltzmann方法,採用D2Q9模型,通過設置模型入口、齣口邊界為非平衡態外推格式,左右邊界及土顆粒邊界為標準反彈格式的邊界條件,建立瞭模擬重構土體細觀滲流場的二維模型。同時,針對一算例編製瞭相應的計算程序,研究瞭恆定流速入滲情況下重構土體的細觀滲流場。研究錶明:土體的滲流方嚮優先選擇連通性較好孔隙所形成的通道,流速受控于通道整體連通性的優劣。整體貫通型的通道流動速度較快,部分連通的孔隙中其流動速度相對較慢。即使跼部孔隙空間較大,其滲流速度仍取決于是否位于貫通型通道上。
진실토체적세관결구유허다개대소불일적토과립단조성,전통사삼수수궤생장법(QSGS)구건적토체결구토과립단비교균균,여실제정황존재교대적차이。위미보저일결함,고필토체공극솔급자상관함수적영향,대전통적사삼수수궤생장법진행개진,실현료경접근우진실토체적세관결구중구。재차기출상기우격자Boltzmann방법,채용D2Q9모형,통과설치모형입구、출구변계위비평형태외추격식,좌우변계급토과립변계위표준반탄격식적변계조건,건립료모의중구토체세관삼류장적이유모형。동시,침대일산례편제료상응적계산정서,연구료항정류속입삼정황하중구토체적세관삼류장。연구표명:토체적삼류방향우선선택련통성교호공극소형성적통도,류속수공우통도정체련통성적우렬。정체관통형적통도류동속도교쾌,부분련통적공극중기류동속도상대교만。즉사국부공극공간교대,기삼류속도잉취결우시부위우관통형통도상。
The mesoscopic structure of real soil consists of numerous particles with different sizes, and yet the traditional reconstruction method of quartet structure generation set (QSGS) produces relatively uniform soil particles,which has significant discrepancy with the actual mesoscopic structure of soil. In order to remedy this deficiency, the QSGS is improved by considering the influences of porosity and autocorrelative function of soil, so that the mesoscopic structure reconfiguration closer to real soil is obtained. Based on the reconfiguration model combined with Lattice Boltzmann method , the D2Q9 model is applied to construct a two dimensional model for simulating mesoscopic seepage field of reconfiguration soil by setting the non-equilibrium extrapolation scheme at the inlet and outlet boundaries, and the bounce-back scheme at the soil particles’ boundary as well as the left and right boundaries. Meanwhile, according to a case study, a corresponding program is developed to simulate mesoscopic seepage field of reconstructed soil with constant inlet seepage velocity. The results show that the pore fluid preferentially flows through the channel with good connectivity. Meanwhile, the flow velocity is controlled by the whole connectivity of the channel. The velocity is much faster in whole-through-channel than that in partial-through-channel. Even if there exists a large pore space, the velocity still depends on whether or not it is on the channel with integral connectivity.