浇筑式沥青混凝土动本构特性试验及数值分析研究

发布时间：2018-08-07 15:34

【摘要】：浇筑式沥青混凝土心墙坝具有施工方便快捷以及严寒条件下亦可施工等优点，应用越来越广。但我国是一个多地震的国家，地震活动分布范围较广，，地震震源较浅，破坏力较大。那么，在地震频发的地区建设浇筑式沥青混凝土心墙坝，其抗震性状究竟如何，是目前急需解决的问题。本文采用试验研究、理论分析和数值模拟相结合的方法。首先，从材料层面研究了浇筑式沥青混凝土材料的动本构特性；其次，从结构层面对浇筑式沥青混凝土心墙坝进行了静动力计算分析和抗震安全评价，探讨了不同厚度的覆盖层对心墙坝动力响应的影响规律；最后，在此基础上，对浇筑式沥青混凝土的静动力本构模型参数进行了敏感性分析。主要研究内容如下：（1）浇筑式沥青混凝土的动本构特性试验研究。选用新疆某浇筑式沥青混凝土材料，进行动本构特性试验。研究浇筑式沥青混凝土材料的动应力-应变、动弹性模量和阻尼比的变化规律；在沥青用量为9.0%和11.0%的条件下，分别探讨不同围压、主应力比和频率对浇筑式沥青混凝土材料的动应力-应变、动弹性模量和阻尼比的影响。研究结果表明：浇筑式沥青混凝土材料动应力-应变骨干曲线变化基本符合双曲线规律；围压和主应力比对材料的动强度、动模量和阻尼比的影响较大，而频率影响较小；沥青用量由9.0%增加到11.0%时，动弹性模量降低幅度达到20％左右。（2）Hardin-Drnevich模型的改进及动力计算程序的编制。根据试验成果，对最大动模量计算公式用于沥青混凝土时进行了改进，运用改进的公式计算值与试验值进行了对比验证。在此基础上，对Hardin-Drnevich模型进行了改进。以有限元软件ADINA为基础，基于改进的Hardin-Drnevich模型，编制了土石坝地震动力计算程序。在此程序的基础上，采用沈珠江残余变形增量模型，编制了土石坝永久变形计算程序，并用算例验证程序计算结果的正确性和适用性。（3）浇筑式沥青混凝土心墙坝动力计算及抗震安全评价。利用ADINA软件和编写的动力计算程序，针对坝高66m的新疆某浇筑式沥青混凝土心墙坝分别进行静动力有限元计算分析；研究了浇筑式沥青混凝土心墙坝的静动力工作性状及变化规律，并对该心墙坝进行抗震安全评价；在此基础上，探讨不同厚度的覆盖层对心墙的影响规律。研究结果表明：1）坝体和心墙绝对加速度及位移的最大值分布规律均表现为从坝基到坝顶逐步增大，在坝顶的附近达到极大值；当心墙沥青用量由9％增大到11％时，心墙的绝对加速度有明显减小。2）浇筑式沥青混凝土心墙坝顶中部及附近永久变形最为明显；心墙竖向永久变形发生在心墙顶的中部附近，最大变形为16.8cm，约占坝高的0.25%；当沥青用量增大到11％时，心墙最大竖向永久变形增大到18.7cm；沥青心墙在地震中的竖向沉陷大于顺河向和横河向的变形，地震变形主要表现为震陷。心墙在两岸坝肩顶部存在低压应力区，该部位是地震灾害工程中容易发生开裂的部位；过渡料层有潜在发生液化的可能性，但主要区域集中在上游过渡料层的顶部，因此基本不会对心墙坝带来危害。3）覆盖层厚度对心墙的绝对加速度和动位移影响较大，对心墙的动应力影响较小。（4）浇筑式沥青混凝土本构模型参数敏感性分析。以新疆某浇筑式沥青混凝土心墙坝为研究对象，分别采用单因素和多因素分析方法，对浇筑式沥青混凝土静动力本构模型参数进行敏感性分析。在多因素分析方法中，分别采用了极差和方差分析方法对考察指标进行了分析，详细探讨浇筑式沥青混凝土本构模型参数对心墙静动力仿真计算结果的敏感性。根据静动力本构模型参数的敏感性分析可知，针对不同的试验指标，参数对试验指标的敏感性会有一定的差异。因此，要根据具体要求选择重要的试验指标，以关键试验指标的参数敏感性为基础，同时兼顾参数对其他试验指标的敏感性进行综合分析研究。
[Abstract]:The pouring asphalt concrete core wall dam has many advantages, such as convenient construction and rapid construction, and the application is more and more widely used. However, China is a country with many earthquakes, the seismic activity is widely distributed, the seismic source is shallow, and the destructive force is great. What is the nature of earthquake is urgently needed to solve.
In this paper, experimental research, theoretical analysis and numerical simulation are used. First, the dynamic constitutive properties of the pouring asphalt concrete are studied from the material level. Secondly, the static and dynamic calculation analysis and the earthquake resistance safety evaluation are carried out on the pouring asphalt concrete core wall dam from the structure layer, and the cover layer with different thickness is discussed. In the end, the parameters of the static and dynamic constitutive model of the pouring asphalt concrete are analyzed. The main contents are as follows:
(1) experimental study on the dynamic constitutive properties of the pouring asphalt concrete. The dynamic constitutive properties of a cast asphalt concrete in Xinjiang were selected to study the dynamic stress strain, the dynamic elastic modulus and the damping ratio of the pouring asphalt concrete. Under the conditions of 9% and 11% of the asphalt, the different girth of the asphalt concrete were discussed. The effect of pressure, principal stress ratio and frequency on the dynamic stress strain, dynamic elastic modulus and damping ratio of pouring asphalt concrete material. The results show that the dynamic stress strain curve of the pouring asphalt concrete material is basically in accordance with the hyperbolic law; the dynamic strength, the dynamic modulus and the damping ratio of the confining pressure and the main stress ratio are to the material. The influence of the asphalt content increased from 9% to 11%, and the dynamic elastic modulus decreased by 20%.
(2) the improvement of the Hardin-Drnevich model and the compilation of the dynamic calculation program. According to the experimental results, the maximum dynamic modulus calculation formula is improved. The calculated value of the improved formula is compared with the test value. On this basis, the Hardin-Drnevich model is improved. The finite element software ADINA is used. Based on the improved Hardin-Drnevich model, the seismic dynamic calculation program of earth rockfill dam is compiled. On the basis of this program, the calculation program of permanent deformation of earth rock dam is compiled with the residual deformation increment model of Shen Zhujiang, and the correctness and applicability of the calculation results are verified by an example.
(3) the dynamic calculation and aseismic safety evaluation of the pouring asphalt concrete core wall dam. The static and dynamic finite element analysis of a pouring asphalt concrete core wall dam in Xinjiang is analyzed with the software of ADINA and the dynamic calculation program written in this paper. The static and dynamic working characters and changes of the pouring asphalt concrete core wall dam are studied. On the basis of this, the effect of the cover layer with different thickness on the core wall is discussed. The results show that: 1) the maximum distribution of the absolute acceleration and displacement of the dam and the heart wall is gradually increased from the dam foundation to the top of the dam, and the maximum value is reached near the top of the dam; the core wall is on the wall. When the amount of asphalt is increased from 9% to 11%, the absolute acceleration of the core wall is obviously reduced by.2). The permanent deformation of the top and near the crest of the concrete core wall is most obvious. The vertical permanent deformation of the core wall occurs near the center of the top of the core wall, and the maximum deformation is about 16.8cm, about 0.25% of the height of the dam. When the asphalt content increases to 11%, the heart wall is increased. The maximum vertical permanent deformation increases to 18.7cm, and the vertical subsidence of the asphalt core wall in the earthquake is greater than the deformation of the river direction and the Henghe direction. The seismic deformation is mainly reflected in the seismic subsidence. The core wall has the low pressure stress zone on the top of the abutment on both sides of the Taiwan Straits, which is the part of the seismic disaster engineering which is prone to crack, and the transition layer has potential liquefaction. But the main area is concentrated in the top of the upstream transition layer, so it is not harmful to the core wall dams.3). The thickness of the cover layer has great influence on the absolute acceleration and dynamic displacement of the core wall, and the dynamic stress of the heart wall is less.
(4) the parameter sensitivity analysis of the pouring asphalt concrete constitutive model. The sensitivity analysis of the parameters of the static and dynamic constitutive model of the pouring asphalt concrete is carried out by the method of single factor and multi factor analysis in Xinjiang. The difference analysis method is used to analyze the investigation index, and the sensitivity of the parameters of the asphalt concrete constitutive model to the static and dynamic simulation results of the core wall is discussed in detail. According to the sensitivity analysis of the parameters of the static dynamic constitutive model, the sensitivity of the parameters to the test indexes will be different. The important test indexes should be selected according to the specific requirements, based on the sensitivity of the parameters of the key test indexes, and the sensitivity of the parameters to other test indexes should be analyzed and studied comprehensively.
【学位授予单位】：新疆农业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TV642;TV312

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