岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2014年
10期
2794-2800
,共7页
张先伟%孔令伟%郭爱国%拓勇飞
張先偉%孔令偉%郭愛國%拓勇飛
장선위%공령위%곽애국%탁용비
结构性黏土%孔隙%压汞试验%固结压力%分形维数
結構性黏土%孔隙%壓汞試驗%固結壓力%分形維數
결구성점토%공극%압홍시험%고결압력%분형유수
structural clay%pore%mercury injection test%consolidation pressure%fractal dimension
为探讨结构性土变形的微观机制,以湛江地区结构性黏土为研究对象,对原状土和压缩试验后土样进行压汞试验,分析不同固结压力下土的孔隙分布、孔径大小以及孔隙结构特征参数的变化规律,辅以SEM图像进行孔隙形态的定性分析,并从分形理论角度对此解释与验证。结果表明,湛江黏土各孔隙组对外力的敏感度与孔隙体积含量正相关。由于压汞过程存在瓶颈效应以及边-面-角的空间接触形式,其结果可能会夸大真实小孔隙的分布密度而低估大孔隙的分布密度。结构性对压缩过程中孔隙分布影响较大,当固结压力增大至结构屈服压力后,孔径为0.01~0.50μm的孔隙组变化明显,孔隙的连通性变差,孔径分布向小孔径范围移动,孤立式孔隙增多,大、中孔隙的界限变得不明显。湛江黏土孔隙具有多重分形特征,据此确定微裂隙、粒间孔隙和孤立孔隙孔径的分界点为0.01μm与0.50μm,同时给出了湛江黏土的孔径界定标准。
為探討結構性土變形的微觀機製,以湛江地區結構性黏土為研究對象,對原狀土和壓縮試驗後土樣進行壓汞試驗,分析不同固結壓力下土的孔隙分佈、孔徑大小以及孔隙結構特徵參數的變化規律,輔以SEM圖像進行孔隙形態的定性分析,併從分形理論角度對此解釋與驗證。結果錶明,湛江黏土各孔隙組對外力的敏感度與孔隙體積含量正相關。由于壓汞過程存在瓶頸效應以及邊-麵-角的空間接觸形式,其結果可能會誇大真實小孔隙的分佈密度而低估大孔隙的分佈密度。結構性對壓縮過程中孔隙分佈影響較大,噹固結壓力增大至結構屈服壓力後,孔徑為0.01~0.50μm的孔隙組變化明顯,孔隙的連通性變差,孔徑分佈嚮小孔徑範圍移動,孤立式孔隙增多,大、中孔隙的界限變得不明顯。湛江黏土孔隙具有多重分形特徵,據此確定微裂隙、粒間孔隙和孤立孔隙孔徑的分界點為0.01μm與0.50μm,同時給齣瞭湛江黏土的孔徑界定標準。
위탐토결구성토변형적미관궤제,이담강지구결구성점토위연구대상,대원상토화압축시험후토양진행압홍시험,분석불동고결압력하토적공극분포、공경대소이급공극결구특정삼수적변화규률,보이SEM도상진행공극형태적정성분석,병종분형이론각도대차해석여험증。결과표명,담강점토각공극조대외력적민감도여공극체적함량정상관。유우압홍과정존재병경효응이급변-면-각적공간접촉형식,기결과가능회과대진실소공극적분포밀도이저고대공극적분포밀도。결구성대압축과정중공극분포영향교대,당고결압력증대지결구굴복압력후,공경위0.01~0.50μm적공극조변화명현,공극적련통성변차,공경분포향소공경범위이동,고입식공극증다,대、중공극적계한변득불명현。담강점토공극구유다중분형특정,거차학정미렬극、립간공극화고립공극공경적분계점위0.01μm여0.50μm,동시급출료담강점토적공경계정표준。
Mercury injection test on Zhanjiang natural soft clay and compressed soil is conducted to obtain the microscopic deformation mechanism of structured soft clay. Evolutions of pore distribution, size, and structural characteristic parameters under different consolidation pressures are analyzed; the pore morphology is further quantitatively analyzed by SEM image, which is explained and testified by fractal theory. The results show that, a positive correlation is shown between the sensitivity of each pore size to external forces and pore volume content. The distribution density of the fine pores might be exaggerated while the one of macro pores might be underestimated in mercury injection test for the bottleneck effect. Pore distribution is affected by structure. When consolidation pressure increases to yield pressure, pores of 0.01-0.50μm are changing obviously, pore connectivity becomes worse, pore size decreases, isolated pores increase, and limits between pore sizes become unobvious. Zhanjiang soft clay has multi-fractal characteristics, the limits for determining micro-pores, interparticle pores and isolated pores are 0.01μm and 0.50μm. Pore size division standard is given.