本文選題：砂土液化　切入點(diǎn)：自由場(chǎng)地　出處：《中國(guó)地震局工程力學(xué)研究所》2017年碩士論文

【摘要】：地震過(guò)程中飽和砂土液化是造成地基失效,引起建筑及工程結(jié)構(gòu)嚴(yán)重破壞的主要原因之一。飽和砂土液化問(wèn)題的研究已取得了豐富的研究成果,這些主要集中在兩方面:其一是基于震害資料利用統(tǒng)計(jì)回歸方法給出的各種經(jīng)驗(yàn)判別方法;其二是利用室內(nèi)動(dòng)三軸試驗(yàn)給出的砂土液化機(jī)理及抗液化強(qiáng)度的試驗(yàn)研究成果。而利用大型振動(dòng)臺(tái)及離心機(jī)振動(dòng)臺(tái)聯(lián)合試驗(yàn)研究液化機(jī)理方面的工作還不多見(jiàn)。本文針對(duì)自由場(chǎng)地飽和砂土,利用大型地震模擬振動(dòng)臺(tái)及離心機(jī)振動(dòng)臺(tái)進(jìn)行了對(duì)比試驗(yàn)研究,并利用有限元軟件Open Sees對(duì)試驗(yàn)結(jié)果進(jìn)行了數(shù)值檢驗(yàn)。目的是分析兩種振動(dòng)臺(tái)試驗(yàn)的合理性,并研究自由場(chǎng)地飽和砂土地震過(guò)程中的加速度變化特征及孔隙水壓力發(fā)展規(guī)律,為可液化場(chǎng)地的土工結(jié)構(gòu)抗震設(shè)計(jì)提供參考。本文完成的主要工作如下:1、設(shè)計(jì)了離心機(jī)振動(dòng)臺(tái)飽和砂土液化試驗(yàn)及大型地震模擬振動(dòng)臺(tái)試驗(yàn)方案,完成了兩種振動(dòng)臺(tái)飽和砂土多工況的地震模擬液化試驗(yàn)。2、對(duì)兩種振動(dòng)臺(tái)試驗(yàn)的結(jié)果進(jìn)行了詳細(xì)的分析,并進(jìn)行了對(duì)比研究,分析結(jié)果表明:離心機(jī)振動(dòng)臺(tái)試驗(yàn)的應(yīng)力與應(yīng)變與原型是一致的,能夠模擬原型應(yīng)力場(chǎng)中的應(yīng)力條件,可再現(xiàn)原型在實(shí)際應(yīng)力條件下的真實(shí)動(dòng)力響應(yīng)。大型振動(dòng)臺(tái)試驗(yàn)在研究重力起主要作用的問(wèn)題時(shí),無(wú)法同時(shí)滿足應(yīng)力應(yīng)變的相似關(guān)系,但仍可以定性的反應(yīng)一些地震液化的規(guī)律。3、利用有限元軟件Open Sees對(duì)兩種振動(dòng)臺(tái)試驗(yàn)進(jìn)行了數(shù)值模擬,結(jié)果表明離心機(jī)振動(dòng)臺(tái)試驗(yàn)結(jié)果與數(shù)值模擬結(jié)果在大震時(shí)兩者的地震反應(yīng)規(guī)律一致,在中震時(shí)上部土層規(guī)律一致。這表明數(shù)值模擬和離心機(jī)振動(dòng)臺(tái)試驗(yàn)差異不大,可以利用有限元軟件Open Sees做數(shù)值模擬研究飽和場(chǎng)地地震液化問(wèn)題。數(shù)值模擬和大型振動(dòng)臺(tái)試驗(yàn)的結(jié)果存在一定差異,大型振動(dòng)臺(tái)試驗(yàn)的液化程度低,大型振動(dòng)臺(tái)試驗(yàn)對(duì)飽和砂土液化模擬是不夠合理的,只能做一些液化規(guī)律的定性研究。
[Abstract]:The liquefaction of saturated sand during earthquake is one of the main causes of ground failure and serious damage to buildings and engineering structures.The research on the liquefaction of saturated sandy soil has obtained a lot of research results, which are mainly focused on two aspects: one is the use of statistical regression method based on seismic disaster data to identify various empirical methods;Secondly, the liquefaction mechanism and liquefaction resistance of sand are studied by dynamic triaxial test.However, it is rare to study liquefaction mechanism by using large shaking table and centrifuge shaking table.In this paper, a comparative experimental study on saturated sand in free site is carried out by using a large earthquake simulation shaking table and a centrifuge shaking table, and the results are tested numerically by the finite element software Open Sees.The aim of this paper is to analyze the rationality of the two shaking table tests and to study the characteristics of acceleration variation and pore water pressure development during the seismic process of saturated sand in free site, and to provide a reference for seismic design of geotechnical structures in liquefiable sites.The main work accomplished in this paper is as follows: 1. The saturated sand liquefaction test of centrifuge shaking table and the test scheme of large-scale earthquake simulation shaking table are designed.The seismic simulation liquefaction test of two kinds of shaking table saturated sand is completed. The results of the two shaking table tests are analyzed in detail, and the results are compared and studied.The results show that the stress and strain of the centrifuge shaking table test are consistent with the prototype, which can simulate the stress conditions in the prototype stress field and reproduce the real dynamic response of the prototype under the actual stress condition.The large-scale shaking table test can not satisfy the similar relation of stress and strain when studying the problem that gravity plays a major role.However, it is still possible to qualitatively reflect some laws of seismic liquefaction. The finite element software Open Sees is used to simulate the two kinds of shaking table tests.The results show that the results of centrifuge shaking table test are consistent with the results of numerical simulation, and the law of the upper soil layer is consistent with that of the medium earthquake.This indicates that there is no difference between the numerical simulation and the shaking table test of centrifuge, so the seismic liquefaction problem in saturated site can be studied by using the finite element software Open Sees.The results of numerical simulation and large-scale shaking table test have some differences. The liquefaction degree of large-scale shaking table test is low, and the large-scale shaking table test is not reasonable to the simulation of saturated sand liquefaction, so it can only do some qualitative research on liquefaction law.
【學(xué)位授予單位】：中國(guó)地震局工程力學(xué)研究所
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TU435

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本文編號(hào)：1692389