断层错动在砂土中传播规律的模型试验研究

Model Test Research of the Fault Slip Spreading Rule in the Soil

利用自行研制的模型箱,以砂土为材料模拟45。和60。倾角下逆断层错动时的裂缝在土体中的发展模式、断层在地表的露头位置、以及断层错动的位移量与土层厚度之间的关系。并得出了一些有意义的结论:破坏面传播到地表所需的断层垂直位移与土体厚度成正比,且断层垂直位移与土体厚度的比值在2%～8%之间;断层的垂直位移△H和断层的水平传播距离L的比值(△H/L)与△H成反比,且比值随着△H的变大而快速减小,最大降幅是45°倾角下砂体厚度为35 cm时,由破坏起始点时的70%,降到断层地表露头时的6.9%;同一倾角,不同土体厚度比较可得:土体厚度越大,传播到地表的水平传播距离越大,且随着土层厚度的增加,破裂在地表露头位置的角度减小等。

This paper performs a model test of the fault slip by using the Nanjing Sand,to simulate the failure mode of the Nanjing Sand and the exposing position of the fault on the ground by simulating the 45°and 60°dip.Then,it obtains the meaningful research results.The fault vertical displacement of the destruction is in direct ratio to the thickness of soil,and the ratio is between 2%-8%.The fault vertical displacementΔH is in inverse proportion to L, which is the horizontal distance of the fault spread（ΔH/L）.And the proportion decreases quickly with theΔH gradually increasing.The most reduction is that the fault dip angle is to 6.9%at the surface occurrence from 70%at the destruction when the dip angle is 45°and the sand height H is 30 cm.For the same angle,the result of a comparison of the different thickness of soil is;the greater the thickness of soil is,the greater the distance of horizontal transmission will be;and with the increase of thickness of the soil body,the angle of crack in the position out of the ground surface decreases,and so on.