This paper presents a general solution for active earth pressure acting on a vertical retaining wall with a drainage system along the soil-structure interface. The backfill has a horizontal surface and is composed of ...This paper presents a general solution for active earth pressure acting on a vertical retaining wall with a drainage system along the soil-structure interface. The backfill has a horizontal surface and is composed of cohesionless and fully saturated sand with anisotropic permeability along the vertical and horizontal directions. The extremely unfavourable seepage flow on the back of the retaining wall due to heavy rainfall or other causes will dramatically increase the active earth pressure acting on the retaining walls, increasing the probability of instability. In this paper, an analytical solution to the Laplace differential governing equation is presented for seepage problems considering anisotropic permeability based on Fourier series expansion method. A good correlation is observed between this and the seepage forces along a planar surface generated via finite element analysis. The active earth pressure is calculated using Coulomb's earth pressure theory based on the calculated pore water pressures. The obtained solutions can be degenerated into Coulomb's formula when no seepage exists in the backfill. A parametric study on the influence of the degree of anisotropy in seepage flow on the distribution of active earth pressure behind the wall is conducted by varying ratios of permeability coefficients in the vertical and horizontal directions,showing that anisotropic seepage flow has a prominent impact on active earth pressure distribution. Other factors such as effective internal friction angle of soils and soil/wall friction conditions are also considered.展开更多
Pressure-induced legislation occasioned by media discourse is actually the result of an information deficit on the part of legislators. If legislators＇ information competency fails to meet the knowledge challenges of...Pressure-induced legislation occasioned by media discourse is actually the result of an information deficit on the part of legislators. If legislators＇ information competency fails to meet the knowledge challenges of the modem legal system and its activities, they will be powerless to resist the infiltration of media discourse. The result is that legislative activities are inextricably intertwined with the media; once a particular social issue is catapulted on to the media agenda, legislators have no choice but to fall into line, creating the phenomenon of pressure-induced legislation. The essential characteristic of law is its inherent constancy and stability, whereas pressure-induced legislation often loses the calmness, objectivity, prudence and comprehensiveness proper to law. Such legislative decision-making runs counter to the inherently rational mechanism of legislation and produces unfair and ineffective redistributive results. Pressure-induced legislation highlights the importance of information in public policy choices and institution design. It would be desirable for the whole legal system aimed at evaluating legislative performance to be introduced so as to provide legislators with a sufficient incentive to remodel their information competency and ensure the scientific nature and rationality of legislation.展开更多
基金supported by the National Key R & D program of China (Grant No. 2016YFC0800204)the National Key Basic Research Program of China (Grant No. 2015CB057801)Natural Science Foundation of China (Grant Nos. 51578499 & 51761130078)
文摘This paper presents a general solution for active earth pressure acting on a vertical retaining wall with a drainage system along the soil-structure interface. The backfill has a horizontal surface and is composed of cohesionless and fully saturated sand with anisotropic permeability along the vertical and horizontal directions. The extremely unfavourable seepage flow on the back of the retaining wall due to heavy rainfall or other causes will dramatically increase the active earth pressure acting on the retaining walls, increasing the probability of instability. In this paper, an analytical solution to the Laplace differential governing equation is presented for seepage problems considering anisotropic permeability based on Fourier series expansion method. A good correlation is observed between this and the seepage forces along a planar surface generated via finite element analysis. The active earth pressure is calculated using Coulomb's earth pressure theory based on the calculated pore water pressures. The obtained solutions can be degenerated into Coulomb's formula when no seepage exists in the backfill. A parametric study on the influence of the degree of anisotropy in seepage flow on the distribution of active earth pressure behind the wall is conducted by varying ratios of permeability coefficients in the vertical and horizontal directions,showing that anisotropic seepage flow has a prominent impact on active earth pressure distribution. Other factors such as effective internal friction angle of soils and soil/wall friction conditions are also considered.
文摘Pressure-induced legislation occasioned by media discourse is actually the result of an information deficit on the part of legislators. If legislators＇ information competency fails to meet the knowledge challenges of the modem legal system and its activities, they will be powerless to resist the infiltration of media discourse. The result is that legislative activities are inextricably intertwined with the media; once a particular social issue is catapulted on to the media agenda, legislators have no choice but to fall into line, creating the phenomenon of pressure-induced legislation. The essential characteristic of law is its inherent constancy and stability, whereas pressure-induced legislation often loses the calmness, objectivity, prudence and comprehensiveness proper to law. Such legislative decision-making runs counter to the inherently rational mechanism of legislation and produces unfair and ineffective redistributive results. Pressure-induced legislation highlights the importance of information in public policy choices and institution design. It would be desirable for the whole legal system aimed at evaluating legislative performance to be introduced so as to provide legislators with a sufficient incentive to remodel their information competency and ensure the scientific nature and rationality of legislation.
