本文選題：巖溶場地 + 地震反應(yīng)��； 參考：《廣西大學(xué)》2015年碩士論文

【摘要】：巖溶場地地震反應(yīng)的研究對確定巖溶區(qū)工程結(jié)構(gòu)的地震動參數(shù)、分析場地及結(jié)構(gòu)的地震響應(yīng)具有重要意義。由于巖溶場地的復(fù)雜性,常規(guī)場地的解析分析方法較難適應(yīng),而實(shí)驗(yàn)室又難以實(shí)現(xiàn)對巖溶場地的整體分析,這些導(dǎo)致巖溶場地進(jìn)行工程建設(shè)時(shí)地震動參數(shù)較難確定。為實(shí)現(xiàn)對巖溶場地地表地震動參數(shù)變化規(guī)律的研究,進(jìn)而在合理范圍內(nèi)確定單一土洞巖溶場地地表主要地震動參數(shù)的計(jì)算公式,在動力有限元的理論基礎(chǔ)上,首先從巖溶場地與非巖溶場地地震響應(yīng)的對比分析入手,利用ABAQUS軟件建立兩種場地的計(jì)算模型,研究巖溶場地由于土洞的存在對地震響應(yīng)的差異,隨后確定影響巖溶場地地震動響應(yīng)的主要因素及其合理范圍,在正交試驗(yàn)的基礎(chǔ)上確定各主要因素的水平值,利用MATLAB對試驗(yàn)值進(jìn)行二次回歸分析,研究巖溶場地地表主要地震動參數(shù)變化規(guī)律,進(jìn)而在合理范圍內(nèi)確定單一土洞巖溶場地主要地震動參數(shù)計(jì)算公式。主要包括以下幾個(gè)方面的內(nèi)容：(1)研究了巖溶場地的特點(diǎn)、場地地震反應(yīng)分析的基本方法,歸納了土體動力本構(gòu)研究現(xiàn)狀和人工邊界的研究現(xiàn)狀,針對選取的地震波進(jìn)行了反演計(jì)算,對場地地震反應(yīng)的基本理論進(jìn)行研究。(2)應(yīng)用ABAQUS軟件建立了巖溶場地和非巖溶場地的場地模型,計(jì)算由于土洞的存在對地表地震動參數(shù)的影響,得出巖溶場地由于土洞的存在對速度和位移影響相對較小,對加速度影響較大,計(jì)算中應(yīng)重視巖溶場地土洞的影響。(3)闡述了正交試驗(yàn)的基本理論和實(shí)現(xiàn)的方法步驟,通過正交試驗(yàn)設(shè)計(jì),分析影響場地地表地震動的主要因素,選取了L16(45)正交表安排數(shù)值試驗(yàn)的試驗(yàn)方案,確定合理的水平值,安排了5因素4水平的有限元正交試驗(yàn)。并且確定了32組場地試驗(yàn)的模型參數(shù),通過ABAQUS建立32組400×400m的場地有限元模型,并進(jìn)行計(jì)算分析。(4)運(yùn)用MATLAB軟件對上述32組有限元試驗(yàn)計(jì)算結(jié)果進(jìn)行二次回歸分析,得到場地地表地震動與各主要影響因素的關(guān)系式,誤差分析效果良好。并對放大系數(shù)λ進(jìn)行深入分析得出,當(dāng)僅有一個(gè)自變量時(shí)λ分別隨著土洞直徑d、覆蓋層厚度H和土體的動彈性模量E變化時(shí)為開口向下的二次函數(shù),當(dāng)僅有一個(gè)白變量h時(shí)λ隨著土洞中心點(diǎn)的深度h變化時(shí)為開口向上的二次函數(shù)。在正交試驗(yàn)水平值取值范圍內(nèi)對λ關(guān)于d的二次函數(shù)進(jìn)行試算發(fā)現(xiàn),在水平值取值范圍內(nèi)存在極大值點(diǎn),即土洞的直徑對地表峰值加速度的影響在某一范圍為增函數(shù),在另一范圍內(nèi)為減函數(shù)。
[Abstract]:The study of seismic response of karst site is of great significance to determine the seismic parameters of engineering structure in karst area and to analyze the seismic response of site and structure.Because of the complexity of karst site, it is difficult to adapt to the analytical analysis method of conventional site, and it is difficult to realize the overall analysis of karst site in laboratory, which leads to the difficulty in determining the parameters of ground motion during the construction of karst site.In order to study the variation law of ground motion parameters in karst site, and then determine the calculation formula of main ground motion parameters in a single soil cave karst site within a reasonable range, on the basis of the theory of dynamic finite element,Starting with the comparative analysis of seismic response between karst site and non-karst site, this paper establishes the calculation model of two kinds of sites by using ABAQUS software, and studies the difference of seismic response between karst site and non-karst site due to the existence of soil cave.Then, the main factors affecting the response of karst ground motion and their reasonable range are determined. Based on the orthogonal test, the horizontal values of the main factors are determined, and the quadratic regression analysis of the test values is carried out by using MATLAB.The variation law of the main ground motion parameters of karst site is studied, and the calculation formula of the main ground motion parameters of a single soil cave karst site is determined within a reasonable range.The main contents are as follows: (1) the characteristics of karst site, the basic method of site seismic response analysis, the present situation of soil dynamic constitutive research and the research status of artificial boundary are summarized.The inversion calculation of selected seismic waves is carried out, and the basic theory of site seismic response is studied. (2) the site models of karst site and non-karst site are established by using ABAQUS software.Because of the influence of soil hole on ground motion parameters, it is concluded that karst site has relatively little influence on velocity and displacement, and greater influence on acceleration because of the existence of soil cave.The basic theory of orthogonal test and the method steps of its realization are expounded in this paper. Through orthogonal test design, the main factors affecting the ground motion of the site are analyzed.In this paper, we select the test scheme of L1645) orthogonal table to arrange the numerical test, determine the reasonable horizontal value, and arrange the finite element orthogonal test with 5 factors and 4 levels.The model parameters of 32 groups of site tests were determined, and 32 groups of finite element models of 400 脳 400m were established by ABAQUS, and calculated and analyzed. (4) using MATLAB software, the results of the 32 groups of finite element tests were analyzed by quadratic regression analysis.The relationship between the ground motion and the main influencing factors is obtained, and the error analysis results are good.By analyzing the magnification factor 位, it is concluded that when there is only one independent variable, 位 is a quadratic function with the change of soil hole diameter d, the thickness of overburden H and the dynamic elastic modulus E of soil, respectively.When there is only one white variable h, 位 is a quadratic function with an opening upward when the depth h of the center point of the soil hole changes.The quadratic function of 位 about d is calculated in the range of horizontal value of orthogonal test. It is found that there exists a maximum point in the range of horizontal value, that is, the influence of the diameter of soil hole on the peak acceleration of the earth surface is an increasing function in a certain range.In another range is a subtraction function.
【學(xué)位授予單位】：廣西大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P315.9;P642.25

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