| Lateral displacement is unavoidable due to the application stress of embankment, so the settlement caused by lateral displacement need to pay attention. How to evaluate the tendency, value of the lateral displacement and the relationship associated with settlement always be a problem in geotechnical engineering. Reviewed the literature of lateral displacement study in the world, studying data about the lateral displacement and settlement from the Luizhou-Nanning passenger dedicated line and through theoretical and three-dimensional numerical analysis have been done in this paper, and the main conclusions are as followings:(1) Based on the solutions for the saturated soil in elastic foundation, this paper considers the influence of the slope of the embankment and the height-width ratio to the lateral displacement further. Using united coordinate, the analysis for the lateral displacement in isotropic foundation with Poisson’s ratio equaled to0.5under the linear, uniform rectangular, triangular and trapezoidal loading have been studied. Relaying on the conclusion gotten previously, the analysis for the Poisson’s ratio less than0.5under the four kinds of loading conditions also been studied.(2) According the settlement monitoring data, the phenomena about with longer period of interval, due to the soil has been consolidated, the effective stress and shear strength has been increased, when reloading, if the critical height is not exceeded, the settlement ratio is decreased comparing with previous loading, but if the critical height is exceeded, the additional load surpassing the structural strength while still smaller than the shear strength, the settlement and lateral displacement will increased dramatically, has been founded. The settlement for two sections with similar condition, the one with the length of12m pile section is smaller than the length of8m pile section, the increment consists13%of the total settlement.(3) Associating the lateral displacement and settlement, these conclusions have been gotten:if the height of embankment does not exceed the over-consolidated critical height, Hsc, the settlement is mainly caused by the consolidation, not only undrained settlement. The average ratio between maximum lateral displacement and settlement under the centre of embankment equals to0.02. If the height of embankment surpasses Hsc, the average ratio during the loading stage equals to0.3, with0.75if there are clay in the underground. During the consolidation period, the average ratio equals to almost0.1.(4) According to the principal about the lateral extrusive volume should be equaled to the volume caused by the settlement, the settlement due to lateral extrusive makes up to20%～40%of the total settlement (with clay in the underground choose the maximum value) in the Liuzhong-Nanning passenger dedicated line. Analyzed the settlement due to lateral extrusive in the reinforce range, these value are smaller than the value in the substratum, varied between10%～15%. So the CFG pile can restrict the lateral deformation and decrease the settlement.(5) Based on the derivation of lateral deformation calculation method, if the modulus select the standard penetration test, and taking into account the critical height of over-consolidated soil, the calculated and measured values roughly coincide.(6) Set up the numerical analysis about the typical section, the analysis tendency is closed to the in situ. Although the ratio between extrusive settlement and total settlement are similar to the in situ, the value are different. This conclusion can be taken, using FLAC3D numerical method can analyze the ratio between extrusive settlement and total settlement and lateral displacement trend effectually, but due to difference in the modulus, the results gotten from numerical method should be modified. |
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