冻结岩石细观结构及温度场数值模拟研究

Meso-structural Character and Numerical Simulation of Temperature Field of Frozen-rock

冻结岩石是一种内部结构及其复杂的岩土工程材料,热学特性与其细观结构密不可分。随着计算机技术的飞速发展,数字图像处理技术已经越来越多地应用于岩土工程领域。利用数字图像处理技术建立冻结岩石的细观结构模型,精确地描述页岩内部的空间结构及细观介质分布的几何形态。利用几何矢量转换技术,将细观结构模型转换为有限元物理模型,分析了负温条件下非均质冻结岩石冻融循环过程中的温度场分布规律。数值模拟结果表明:岩石的细观结构决定了冻融岩石温度场的分布形态,对岩石冻融损伤破坏过程产生不可忽视的影响。文章所提出的方法可实现考虑冻融岩石细观结构的冻土热、力学特性的定量分析。

The internal structure of frozen-rock is complicated and the thermal characteristics of frozen-rock is closely related to its meso-structure.With the quick development of computer technique,digital image processing has been successfully used in geotechnical engineering.Based on digital image processing,meso-structure of frozen-rock by taking into account the actual material inhomogeneity is constructed.Digital image processing method can be used as a measurement tool to construct a digital representation for actual spatial distribution of different materials in rock.The meso-structural model can accurately describe the spatial distribution of rock and meso-medium.Using geometry transformation,the meso-structure model of frozen-rock under dual digital image has been translated into a document format which can be received by finite element software.By this step,the numerical simulation of actual meso-structures of frozen-rock is carried out.The numerical simulation for temperature field law of frozen-rock during frost-thaw cycles under subzero temperature condition has been done.Simulation results show that： meso-structure of rock determines distribution of temperature field of freezing-thawing rock and has an indispensable influence on frost-thaw damage process.The proposed approach can grope the hazard reasons in the eyes of meso-scale and provide a new way to research the inherent mechanism of frost heave and thaw settlement and the consolidation of frozen ground.This approach can be used to realize the quantitative analysis of thermal and mechanical characteristics of frost-thaw rock accounting meso-structure of rock.