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1.
INTRODUCTIONItisimportanttoforecastandcalculatetheroleofconsolidationinstrengtheningsoftsoilground .Forconvenientuseinengineering ,themodelofconsolidationwasreducedtoaone di mensionalprobleminspatialdomain .SinceTerzaghiestablishedone dimensionallinearco…  相似文献   

2.
This paper presents a semi-analytical method to solve one dimensional consolidation problem by taking consideration of varied compressibility of soil under cyclic loading. In the method, soil stratum is divided equally into n layers while load and consolidation time are also divided into small parts and time intervals accordingly. The problem of one-dimensional consolidation of soil stratum under cyclic loading can then be dealt with at each time interval as one-dimensional linear consolidation of multi-layered soils under constant loading. The compression or rebounding of each soil layer can be judged by the effective stress of the layer. When the effective stress is larger than that in the last time interval, the soil layer is compressed, and when it is smaller, the soil layer rebounds. Thus, appropriate compressibility can be chosen and the consolidation of the layered system can be analyzed by the available analytical linear consolidation theory. Based on the semi-analytical method, a computer progra  相似文献   

3.
INTRODUCTION The propagation of stress-waves in an elasticmedium containing a cavity that are due to arbitrarydynamic loading applied on the cavity is of greatimportance in the fields of seismology, geophysicalprospecting, underground tunnels and deeply buriedpipelines, particularly as a model of an earthquakesource. Ben-Menahem and Cisternas (1963) devel-oped the theory for the dynamic response of an elastichalf-space medium to an explosion spherical cavity.Norwood and Miklowitz (…  相似文献   

4.
The variation of effective stress ratio of stratfied soil with semi-pervious boundaries and under cyclic loading was analyzed on the basis of Terzaghi's one-dimensional consolidation assumptions. A solution by Laplace Transform was obtained for the case when the soil was under time-varied loading. With numerical inversion of Laplace Transform, some useful results were obtained for several kinds of commonly encountered loadings. The results can be meaningful in engineering practice.  相似文献   

5.
INTRODUCTION An important problem in foundation engineeringis the determination of the rate of settlement of a raftfoundation placed on a deep clay layer. Gibson andMcNamee (1957), and McNamee and Gibson (1960a;1960b) considered the problem of normal uniformloading applied to the surface of a half-space andshowed that one-dimensional theory gives a markedunderestimate of the rate of settlement. This theorycorresponds to the case of a perfectly flexible footing.However, it is often…  相似文献   

6.
The variation of effective stress ratio of stratfied soil with semi-pervious boundaries and under cyclic loading was analyzed on the basis of Terzagh's one-dimensional consolidation assumptions. A solution by Laplace Transform was obtained for the case when the soil was under time-varied loading. With numerical inversion of Laplace Transform, some useful results were obtained for several kinds of commonly encountered loadings. The results can be meaningful in engineering practice. Project supported by the National Natural Science Foundation of China (No. 59908012) and Fok Ying Tung Education Fundation (No. 81067), Education Ministry of China.  相似文献   

7.
INTRODUCTION Conventional consolidation analysis based on Terzaghi’s one-dimensional theory neglects the non-linearity of soil for the sake of mathematical expediency, which is considered to be one of the theory’s shortcomings. Many researchers have pro-posed one-dimensional (1D) consolidation models where the coefficient of volume compressibility mv, coefficient of permeability kv, and coefficient of consolidation cv, vary with either depth or time. Schiffman (1958), Davis and Raymon…  相似文献   

8.
Based on consolidation equations proposed for unsaturated soil, an analytical solution for 1D consolidation of an unsaturated single-layer soil with nonhomogeneous mixed boundary condition is developed. The mixed boundary condition can be used for special applications, such as tests occur in laboratory. The analytical solution is obtained by assuming all material parameters remain constant during consolidation. In the derivation of the analytical solution, the nonhomogeneous boundary condition is first transformed into a homogeneous boundary condition. Then, the eigenfunction and eigenvalue are derived according to the consolidation equations and the new boundary condition. Finally, using the method of undetermined coefficients and the orthogonal relation of the eigenfunction, the analytical solution for the new boundary condition is obtained. The present method is applicable to various types of boundary conditions. Several numerical examples are provided to investigate the consolidation behavior of an unsaturated single-layer soil with mixed boundary condition.  相似文献   

9.
用Matlab求解系统的状态方程,可用仿真函数、迭代计算和拉氏变换方法得到其数值解、解析解和波形图。用lsim仿真函数求系统响应的数值解;迭代法用来求解离散系统状态方程,连续系统状态方程通过离散化后也可用迭代法;连续系统状态方程采用拉氏变换可得到解析结果。通过实例分析,展现了Matlab在系统状态变量分析方面的优越性,不仅使系统状态方程的计算变得简单,而且可得到可视化的结果。  相似文献   

10.
本介绍了一维波动方程Cauchy问题解的表达式的另一种推导方法,并简单考虑了其解的存在条件.首先用Fourier变换、Laplace变换及其它们的相关性质,获得了与参考献一致的解的表达式,然后通过比较这两种不同的推导方法,可知本所述的推导方法具有过程简单、浅显易懂等优点.  相似文献   

11.
Biot's dynamic consolidation equations and Hankel transform were used to derive the integral solutions of stress and displacement for axisymmetric harmonic excitations in the two-phase saturated soil with subjacent rock-stratum. The influence of the coefficient of permeability and loading frequency on the soil displacement at the ground surface were studied. The results showed that higher loading frequency led to more dynamic characteristics; and that the effect of the soil permeability was more obvious at higher frequencies.  相似文献   

12.
Stable response of axisymmetric two-phase water-saturated soil   总被引:1,自引:0,他引:1  
Biot's dynamic consolidation equations and Hankel transform were used to derive the integral solutions of stress and displacement for axisymmetric harmonic excitations in the two-phase saturated soil with subjacent rock-stratum. The influence of the coefficient of permeability and loading frequency on the soil displacement at the ground surface were studied. The results showed that higher loading frequency led to more dynamic characteristics; and that the effect of the soil permeability was more obvious at higher frequencies.  相似文献   

13.
利用分离变量法,Laplace变换及广义Mittage-Leffler函数,给出了有限区间上分数阶扩散-波方程混合问题的精确解.  相似文献   

14.
Newton’s theory of gravitation solvedmany problems of celestialmechanics but led to some major problems, one of which was that it gave rise to a serious paradox discussed in this article. The paradox has a number of manifestations one of which is presented here. It should be remembered that the root cause of all these paradoxes is fundamentally the same. Laplace attempted an ad hoc solution. However, it could not be mathematically demonstrated that his proposal solves the difficulty. In this article, it is shown that his suggestion removes the problem. A physical phenomenon that can justify Laplace’s suggestion is also mentioned briefly. This article also poses an interesting mathematical problem that can be attempted by interested readers. The computational solution is presented here.  相似文献   

15.
In this work, semi-analytical methods were used to solve the problem of 1-D consolidation of non-homogeneous soft clay with spatially varying coefficients of permeability and compressibility. The semi-analytical solution was programmed and then verified by comparison with the obtained analytical solution of a special case. Based on the results of some computations and comparisons with the 1-D homogeneous consolidation (by Terzaghi) and the 1-D non-linear consolidation theory (by Daviset al.) of soft clay, some diagrams were prepared and the relevant consolidation behavior of non-homogeneous soils, is discussed. It was shown that the result obtained differs greatly from Terzaghi’s theory and that of the non-linear consolidation theory when the coefficients of permeability and compressibility, vary greatly.  相似文献   

16.
In this paper, a semi-analytical method for the analysis of pile-supported embankments is proposed. The mathematic model describes the cooperative behavior of pile, pile cap, foundation soil, and embankment fills. Based on Terzaghi??s 1D consolidation theory of saturated soil, the consolidation of foundation soil is calculated. The embankments with two different types of piles: floating piles and end-bearing piles are investigated and discussed. The results of axial force and skin friction distributions along the pile and the settlements of pile-supported embankments are presented. It is found that it takes a longer time for soil consolidation in the embankment with floating piles, compared with the case using end-bearing piles. The differential settlement between the pile and surrounding soil at the pile top is larger for the embankment with end-bearing piles, compared with the case of floating piles.  相似文献   

17.
本文是用连分式求解离散Master方程。我们仅限于考虑一个自变量的情况,并让转移速率W(n+2,n)≠0,W(n-2,n)=0。利用Laplace变换和逆变换,我们求出了这种限制下的两“粒子”跳跃离散Master方程的与时间有关的严格解,它服从一些循环关系。  相似文献   

18.
在桩基础设计中,由于认识上的问题,往往只考虑持力层是否会破坏,而忽略了特定应用条件下持力层下卧软土固结变形带来的问题。通过工程实例的分析对该问题进行了分析阐述。  相似文献   

19.
Delta function is an important function in mathematics and physics. In this paper, the Laplace transforms of δ(t)and δ(t-τ)have been discussed in detail. After the Laplace transform of δ(t)is analyzed, the author has found that three aspects should be taken into account, i.e. τ→0+, τ→0- andτ=0; and it is the same with the Laplace transform of δ(t-τ). Then the results of the Laplace transform of Delta function have been obtained in a rigorous and comprehensive sense.  相似文献   

20.
研究了梯度饱和土层在外荷载下的固结作用,利用Biot理论给出了固结的基本微分方程,一些材料常数假设为指数模型,当梯度系数为零时,退化为一维均匀饱和土层的固结,利用分离变量等方法,得到透水和不透水边界条件下孔隙压力,给出了固结度曲线。当梯度系数不为零时,给出了梯度饱和土在外荷载下的孔隙压力,利用固结度的定义,数值算例出了梯度饱和土层的固结度变化曲线,分析和讨论了梯度系数等对固结度的影响。这些结果对地基下沉量计算和预测有一定的理论价值和意义。  相似文献   

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