岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2013年
10期
2774-2780
,共7页
王媛%冯迪%陈尚星%吴昊宸
王媛%馮迪%陳尚星%吳昊宸
왕원%풍적%진상성%오호신
裂隙土%分形%摄影法%分维数%表征单元体(REV)
裂隙土%分形%攝影法%分維數%錶徵單元體(REV)
렬극토%분형%섭영법%분유수%표정단원체(REV)
cracked soil%fractal%photograph method%fractal dimension%representative elementary volume (REV)
由于干湿循环、剪切或其它作用，自然界土壤表面发育着大量裂隙。裂隙相互连接形成网络，裂隙网络是一个随机无序的系统，常规统计方法描述裂隙的分布特征存在很大的难度。网状土体裂隙一般具有分形特征，可以用分维数来进行描述。用数码相机拍摄土体表面的裂隙，将其转换成灰度图像，并结合分形理论，建立了摄影法测定土体裂隙分维数的方法，得到了土体裂隙的分维数。根据表征单元体的物理意义，建立了基于分维数估算表征单元体的方法，并对实例进行了分析。研究表明：分维数随裂隙密度，裂隙宽度和次一级裂隙发育程度的增大而增大；表征单元体与裂隙的密度均匀性和隙宽均匀性相关，基于分维数估算表征单元体的方法简便可行。
由于榦濕循環、剪切或其它作用，自然界土壤錶麵髮育著大量裂隙。裂隙相互連接形成網絡，裂隙網絡是一箇隨機無序的繫統，常規統計方法描述裂隙的分佈特徵存在很大的難度。網狀土體裂隙一般具有分形特徵，可以用分維數來進行描述。用數碼相機拍攝土體錶麵的裂隙，將其轉換成灰度圖像，併結閤分形理論，建立瞭攝影法測定土體裂隙分維數的方法，得到瞭土體裂隙的分維數。根據錶徵單元體的物理意義，建立瞭基于分維數估算錶徵單元體的方法，併對實例進行瞭分析。研究錶明：分維數隨裂隙密度，裂隙寬度和次一級裂隙髮育程度的增大而增大；錶徵單元體與裂隙的密度均勻性和隙寬均勻性相關，基于分維數估算錶徵單元體的方法簡便可行。
유우간습순배、전절혹기타작용，자연계토양표면발육착대량렬극。렬극상호련접형성망락，렬극망락시일개수궤무서적계통，상규통계방법묘술렬극적분포특정존재흔대적난도。망상토체렬극일반구유분형특정，가이용분유수래진행묘술。용수마상궤박섭토체표면적렬극，장기전환성회도도상，병결합분형이론，건립료섭영법측정토체렬극분유수적방법，득도료토체렬극적분유수。근거표정단원체적물리의의，건립료기우분유수고산표정단원체적방법，병대실례진행료분석。연구표명：분유수수렬극밀도，렬극관도화차일급렬극발육정도적증대이증대；표정단원체여렬극적밀도균균성화극관균균성상관，기우분유수고산표정단원체적방법간편가행。
Natural soil may be cracked due to wetting-drying cycles, shearing or other effects. Most cracks tend to be connected and form a network. A crack network on a natural soil surface is a random and disordered system. It is hard to describe the distribution characteristics of cracks by the traditional statistical method. Generally, the crack network has fractal dimension. The theory of fractal dimension can be used to describe the distribution characteristics of cracks. Crack images are taken by a digital camera on a soil surface and converted to gray images. A method for determining fractal dimension by photograph is established based on the fractal theory. Then, the fractal dimension of soil cracks can be obtained. According to the physical meaning of representative elementary volume (REV), a method for estimating the cracked soil’s REV based on the fractal dimension is presented;and some examples are analyzed. The results show that the fractal dimensions are increased with the increasing of crack density, crack aperture and the development of secondary crack. The REV is related to the homogeneity of crack density and crack aperture. It is easy and credible to estimate the cracked soil’s REV by the method mentioned above.
