Work and energy equations and the principle of generalized effective stress for unsaturated soils

The effective stress principle has been efficiently applied to saturated soils in the soil mechanics and geotechnical engineering practice; however, its applicability to unsaturated soils is still under debate. The appropriate selection of stress state variables is essential for the construction of constitutive models for unsaturated soils. Owing to the complexity of unsaturated soils, it is difficult to determine the deformation and strength behaviors of unsaturated soils uniquely with the previous single-effective-stress variable theory and two-effective-stress-variable theory in all the situations. In this paper, based on the porous media theory, the specific expression of work is proposed, and the effective stress of unsaturated soils conjugated with the displacement of the soil skeleton is further derived. In the derived work and energy balance equations, the energy dissipation in unsaturated soils is taken into account. According to the derived work and energy balance equations, all of the three generalized stresses and the conjugated strains have effects on the deformation of unsaturated soils. For considering these effects, a principle of generalized effective stress to describe the behaviors of unsaturated soils is proposed. The proposed principle of generalized effective stress may reduce to the previous effective stress theory of single-stress variable or the two-stress variables under certain conditions. This principle provides a helpful reference for the development of constitutive models for unsaturated soils.

制造业技术工人工作-家庭关系的影响因素及其作用机制

The work-family relations included positive relationship (work-family enrichment) and negative relationship (work-family conflict). Along with the development of positive psychology, the researchers turned their focus from work-family conflict to work-family enrichment. On the other hand, the research between work and family had just started and most attention was fix on work-family conflict. This research based on the skilled workers in manufacturing, and tried to discuss antecedents and the machanism of work-family relations through a series research which include action relation among job characteristics, work-family relations and outcomes of work, and the action relation among job resource、work-family relations、marital adjustment、work outcomes and role salience. This subject made the investigation to the workers who are working in manufacturing through literature research, questionnaire surveys and other methods. In this subject, several statistical techniques such as Explore Factor Analysis（CFA）,Structural Equation Modeling（SEM）, multiple-group Analysis were used to get the following conclusion: Firstly, work-family enrichment was an independent variable in work-family conflict, which had more extensively influence. Work-family conflict would increase accompany with the increasing of job demand, and it also would enhance negative work outcomes; work-family enrichment was effected by both job demand and job resource, and it made positive influence to positive and negative work outcomes. Secondly, marital adjustment penetrated into work domain through work-family enrichment inner effect mechanism, and influenced the work outcomes. The work→family enrichment and family→work enrichment could facilitate mutually, marital adjustment influenced the work outcome by the reciprocal relationship of work→family enrichment ↔ family→work enrichment. Finally, the family-role salience had directed loop-enhanced effect to organizational commitment and the importance could also enhance the positive function of work→family enrichment to organizational commitment.