The factors influencing on soil expansion are reviewed in the paper. A mechanics model to determine swelling potential of expansive soils is presented. The mechanics model is based on the softening of expansive soil f...The factors influencing on soil expansion are reviewed in the paper. A mechanics model to determine swelling potential of expansive soils is presented. The mechanics model is based on the softening of expansive soil following absorption of water. The constitutive relationships of the mechanics model include the relationship among swelling under free load, swelling under load, and vertical pressure, and the relationship of swelling under free loading and swelling pressure. A concept of additional compression modulus is introduced and the method determining the modulus is proposed. Finally, the predicted results of swelling potential using the mechanics model compare well with the measured data.展开更多
Slope stability analysis is a classical mechanical problem in geotechnical engineering and engineering geology.It is of great significance to study the stability evolution of expansive soil slopes for engineering cons...Slope stability analysis is a classical mechanical problem in geotechnical engineering and engineering geology.It is of great significance to study the stability evolution of expansive soil slopes for engineering construction in expansive soil areas.Most of the existing studies evaluate the slope stability by analyzing the limit equilibrium state of the slope,and the analysis method for the stability evolution considering the damage softening of the shear zone is lacking.In this study,the large deformation shear mechanical behavior of expansive soil was investigated by ring shear test.The damage softening characteristic of expansive soil in the shear zone was analyzed,and a shear damage model reflecting the damage softening behavior of expansive soil was derived based on the damage theory.Finally,by skillfully combining the vector sum method and the shear damage model,an analysis method for the stability evolution of the expansive soil slope considering the shear zone damage softening was proposed.The results show that the shear zone subjected to large displacement shear deformation exhibits an obvious damage softening phenomenon.The damage variable equation based on the logistic function can be well used to describe the shear damage characteristics of expansive soil,and the proposed shear damage model is in good agreement with the ring shear test results.The vector sum method considering the damage softening behavior of the shear zone can be well applied to analyze the stability evolution characteristics of the expansive soil slope.The stability factor of the expansive soil slope decreases with the increase of shear displacement,showing an obvious progressive failure behavior.展开更多
A computational method and a mechanical model for evaluating the vertical dynamic harmonic response characteristics of a single pile embedded in non-homogeneous soil layers and subjected to harmonic loadings were esta...A computational method and a mechanical model for evaluating the vertical dynamic harmonic response characteristics of a single pile embedded in non-homogeneous soil layers and subjected to harmonic loadings were established based on a certain assumption and the improved dynamic model of beam-on-Winkler foundation by using the principle of soil dynamics and structure dynamics. Both non-homogeneity of soil strata and softening effect of soil layer around the pile during vibration were simultaneously taken into account in the proposed computational model. It is shown through the comparative study on a numerical example that the numerical results of dynamic response of the single pile computed by the proposed method are relatively rational and can well agree with the numerical results computed from the well-known software of finite element method. Finally the parametric studies were conducted for a varied range of main parameters to discuss the effects of relevant factors on dynamic responses of the single pile embedded in non-homogeneous layered soils excited by harmonic loading with different frequencies.展开更多
文摘The factors influencing on soil expansion are reviewed in the paper. A mechanics model to determine swelling potential of expansive soils is presented. The mechanics model is based on the softening of expansive soil following absorption of water. The constitutive relationships of the mechanics model include the relationship among swelling under free load, swelling under load, and vertical pressure, and the relationship of swelling under free loading and swelling pressure. A concept of additional compression modulus is introduced and the method determining the modulus is proposed. Finally, the predicted results of swelling potential using the mechanics model compare well with the measured data.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFC1509901).
文摘Slope stability analysis is a classical mechanical problem in geotechnical engineering and engineering geology.It is of great significance to study the stability evolution of expansive soil slopes for engineering construction in expansive soil areas.Most of the existing studies evaluate the slope stability by analyzing the limit equilibrium state of the slope,and the analysis method for the stability evolution considering the damage softening of the shear zone is lacking.In this study,the large deformation shear mechanical behavior of expansive soil was investigated by ring shear test.The damage softening characteristic of expansive soil in the shear zone was analyzed,and a shear damage model reflecting the damage softening behavior of expansive soil was derived based on the damage theory.Finally,by skillfully combining the vector sum method and the shear damage model,an analysis method for the stability evolution of the expansive soil slope considering the shear zone damage softening was proposed.The results show that the shear zone subjected to large displacement shear deformation exhibits an obvious damage softening phenomenon.The damage variable equation based on the logistic function can be well used to describe the shear damage characteristics of expansive soil,and the proposed shear damage model is in good agreement with the ring shear test results.The vector sum method considering the damage softening behavior of the shear zone can be well applied to analyze the stability evolution characteristics of the expansive soil slope.The stability factor of the expansive soil slope decreases with the increase of shear displacement,showing an obvious progressive failure behavior.
基金the Post Doctor Science Foundation of China(Grant No.20060390806 &20060400241)the Taishan Scholar Foundation of Shandong ProvinceScience Development Foundation of Shandong University of Science and Technology(Grant No.05g002)
文摘A computational method and a mechanical model for evaluating the vertical dynamic harmonic response characteristics of a single pile embedded in non-homogeneous soil layers and subjected to harmonic loadings were established based on a certain assumption and the improved dynamic model of beam-on-Winkler foundation by using the principle of soil dynamics and structure dynamics. Both non-homogeneity of soil strata and softening effect of soil layer around the pile during vibration were simultaneously taken into account in the proposed computational model. It is shown through the comparative study on a numerical example that the numerical results of dynamic response of the single pile computed by the proposed method are relatively rational and can well agree with the numerical results computed from the well-known software of finite element method. Finally the parametric studies were conducted for a varied range of main parameters to discuss the effects of relevant factors on dynamic responses of the single pile embedded in non-homogeneous layered soils excited by harmonic loading with different frequencies.
