论文部分内容阅读
本文通过数值计算研究了入射平面P波在饱和半空间中洞室周围散射问题,分析了入射波频率和角度、边界渗透条件、孔隙率、泊松比等参数对散射的影响。研究表明,平面P波入射情况下,饱和半空间和单相(干土)半空间中洞室附近地表位移幅值的差别很大,干土情况的水平位移幅值相对较大,饱和情况的竖向地表位移幅值相对较大;由于波在洞室附近的干涉,饱和情况与干土情况的地表位移出现相位漂移。随着孔隙率的增大,洞室附近水平地表位移幅值逐渐减小,竖向地表位移幅值则逐渐增大;当孔隙率较低时,边界渗透条件对地表位移幅值的影响很小,而当孔隙率较大时,边界渗透条件的影响则不可忽视,不透水情况下,水平和竖向地表位移幅值的峰值均相对较大;随着入射频率的增加,孔隙率的影响逐渐增大,而且不透水情况下孔隙率的影响相对较大。随着泊松比的增大,洞室附近水平地表位移幅值逐渐降低,竖向地表位移幅值则逐渐增大;泊松比较小时,边界渗透条件对位移幅值的影响较大,泊松比较大时,边界渗透条件对位移幅值的影响则较小;随着入射频率的增加,泊松比的影响逐渐增大。当孔隙率较小时,半空间地表和洞室表面孔隙水压幅值较小,但空间变化比较剧烈,随着孔隙率的增大,孔隙水压逐渐增大但空间变化逐渐平缓;随着入射频率的增加,孔隙水压幅值逐渐增大,且孔隙水压的空间变化逐渐变得复杂。
In this paper, we study the scattering of incident plane P waves in the cavity surrounding saturated half-space by numerical calculation. The effects of incident wave frequency and angle, boundary infiltration conditions, porosity and Poisson’s ratio on the scattering are analyzed. The results show that the amplitude of the surface displacement near the cavern in the saturated half-space and the single-phase (dry soil) half-space is very large under the condition of the plane P-wave incident, and the amplitude of the horizontal displacement of the dry soil is relatively large. The amplitude of vertical surface displacement is relatively large. Due to the interference of the wave in the vicinity of the cavern, there is a phase shift of the surface displacements in the saturated and dry earth conditions. With the increase of porosity, the amplitude of horizontal surface displacement decreases gradually and the amplitude of vertical surface displacement increases gradually. When the porosity is low, the effect of boundary infiltration on ground displacement amplitude is small , While when the porosity is large, the influence of the boundary infiltration conditions can not be neglected. In the case of impermeable water, the peak values of the horizontal and vertical ground surface displacements are all relatively large. With the increase of incident frequency, the influence of porosity gradually Increase, and the impact of porosity is relatively large impervious case. With the increase of Poisson’s ratio, the amplitude of horizontal surface displacement near the cavern gradually decreases and the amplitude of vertical surface displacement gradually increases. When the Poisson’s ratio is small, the influence of the boundary infiltration conditions on the displacement amplitude is larger. Poisson When larger, the influence of boundary infiltration conditions on displacement amplitude is smaller; as the incident frequency increases, the influence of Poisson’s ratio increases. When the porosity is small, the pore water pressure on the surface of the half space and the surface of the chamber is smaller, but the space changes more intensely. With the increase of the porosity, the pore water pressure gradually increases but the space changes gently. As the frequency increases, the pore water pressure amplitude gradually increases, and the spatial variation of pore water pressure gradually becomes complicated.