土木工程外文翻譯--軟土地基上分期施工的路堤沉降預(yù)測(cè)方法-建筑結(jié)構(gòu)-文庫(kù)吧
2025-04-17 14:03 本頁(yè)面
【正文】 ction for embankments on soft clays are of the following types: (1) Prediction of the deformation behavior of stage construction from the results of borings and tests . (2) Prediction of the final settlement at permanent load from the behavior of the first stage construction. (3) Prediction of the post construction settlement at the permanent load and corresponding time of surcharge removed from the behavior of the surcharge. The first of these problems is heavily dependent on the theory , which is necessary in design. The other two predictions require empirical rather than theoretical methods because they are based on observational data. In any case , the fact that the second and third predictions are derived from field observations makes them more reliable than the theoretical predictions . Leroueil et al revealed the effective stress path and analyzed the relationship between vertical settlement and lateral displacement during stage construction. Stamatopoulos and Kotzias developed a method to determine the final settlement at permanent load from the behavior of surcharge, but it is based on the elastic theory and difficult to calculate the rate of the settlement . The hyperbolic method is based on the total load settlement relationship to predict the final settlement , which is not sensitive to the nature of the initial loading condition. This paper presented a method for the prediction of the final settlement at permanent load from the behavior of the first stage construction based on the Asaoka method. 2. Stage observational method Asaoka proposed an‘observational procedure’to estimate the final settlement and in2situ coefficient of consolidation from the field observational data. This method is being increasing popular because of its simplicity and effectivity. The method is based on the fact that one dimensional consolidation settlements S0 , S1 , S2 , … ， Sj at times 0 ， ? t ， 2? t ， … ， j? t can be expressed as a first order approximation by which represents a straight line in a Sj vs Sj1 plot , where 0? is the intercept and 1? is the slope of the line. When the ultimate settlement has been reached : Sj= Sj1=Sf , therefore ,the ultimate settlement Sf can be given by and ln 1? = 26H tCV? (both top and bottom drainage) ln 1? = 22H tCV? (top drainage) The constant 1? has been suggested by Magnan and Deroy to be related to the coefficient of consolidation Cv as follows: for horizontal radial drainage only for vertical drainage only where De , H are the drainage path length respectively. Asaoka method also stated that the straight line in Sj Sj1 space would moved up in the case of multistaged loading , moreover , the shifted lines bee almost parallel to the initial when the settlement is relatively small pared to the thickness of clay layer. However , it is not discussed and provided how to determine the shift distance from the line of first stage to the line of the next stage. In the expression (1) ,when j = 0 that is : t = 0 and S(t=0) = S0 ,where t can be taken as 0 from any time after loading works . If t is set as 0 at the exact time once the load is exerted , then , Sj1 bees 0。 This means that Asaoka method can be extended to obtain the construction settlement , which equals to the intercept 0? of the liner line in the space Sj Sj1, where t = 0 is set just after loading. Moreover , this immediate settlement contributes the shift distance of the parallel lines during stage construction. In fact , from the derivation of the Asaoka method , the settlement of soil layers can be expressed as and ?????? ?????????? )(51)(31)(41)(21),( 243242 FCZFCZZFTCZTCZTzt VVVV ?。。。? where T and F are two unknown function of time. With the vertical drainage boundary conditions and at the
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