混凝土坝真实性态仿真与联合筑坝安全评价方法研究
发布时间：2019-02-16 06:05
【摘要】：本文研究着眼于水工结构领域两个问题,混凝土坝真实性态仿真与联合筑坝安全评价。联合筑坝是指碾压混凝土与常态混凝土联合构筑坝体的新技术,即大坝在不同坝段、同坝段不同高程、同高程不同区域存在常态混凝土与碾压混凝土共用的情况。这一新技术不仅加快向家坝工程的大坝施工速度,保障工程按期蓄水发电,同时也节约了工程建设成本,是筑坝理念和筑坝技术上的进步与创新,具有显著的经济和社会效益。采用碾.压混凝土和常态混凝土联合筑坝,由于两种混凝土的热学、力学特性的差异,坝体应力与传统的常态混凝土坝和碾压混凝土坝相比都会存在一定差异,进而可能影响到联合筑坝坝体的抗滑稳定特性,但目前规范难以很好评估。基于此,本文对比了水利规范、电力规范、分区安全系数法、直接强度折减法与全过程仿真后强度折减法五种评价方法,并提出了分区抗滑安全系数的概念,得出以下结论:(1)五种评价方法都有其优势与不足,方法一(水利规范刚体极限平衡法)形式简单,适用性强;方法二(分区安全系数法)考虑了坝体应力变形影响,可以计算坝体在规范荷载作用下不同分区的抗滑稳定安全系数,但目前缺乏工程应用经验;方法三(电力规范刚体极限平衡法)以分项系数的方式将材料参数的不确定性、荷载的不确定性进行了细化,但都无法考虑坝体应力分布差异对稳定的影响;方法四(直接有限元强度折减法)较前三种方法的优势之处在于能够模拟坝体强度降低过程中的结构渐进破坏过程,但无法考虑施工期与运行期应力及材料时变效应;出于模拟更贴近真实稳定状态的角度来讲,全过程仿真后强度折减法(方法五)最优,可以在更真实模拟大坝温度、应力、变形时间空间场的基础上考虑长期运行对材料弱化作用,进而通过强度折减确定强度储备系数,对于大型、复杂工程问题建议采用此方法。(2)弹模差异、纵缝性态对最终强度储备系数没有显著影响,但在渐进失稳的过程中,坝体前部区域混凝土弹模越大于后部,则会造成坝踵应力越大,塑性区越容易扩展至帷幕处;坝体前部区域混凝土弹模小于后部时则与前后部混凝土弹模相当时差别不大。(3)强度准则的选择也对计算结果有影响,选择M-C强度准则进行强度折减计算能够得到偏安全的结果。(4)纵缝性态差异对整坝强度储备系数影响不大,但对坝体渐进破坏过程及对分区抗滑稳定安全系数有较显著的影响,缝强度越低屈服区面积发展越快,缝强度提高更有利于坝体的整体稳定性。真实性态仿真基于有限元方法,是对传统有限元方法更进一步发展,可以模拟自第一仓混凝土浇筑、温度控制、封拱、蓄水乃至长期运行的全过程工作性态,可以得到每一天的温度场、渗流场、位移场和应力场。本文采用有限元仿真分析方法,以向家坝工程和锦屏一级为例,结合工程实测资料和反演分析,研究了重力坝和拱坝施工运行全过程的真实工作性态,主要结论如下:(1)采用仿真分析方法研究,基于实测资料,可以较好的反演分析工程的实际工作性态;(2)向家坝联合筑坝条件下交界面不会产生过大温度梯度,大坝最高温度和降温过程基本满足防裂要求;应力基本都在可控范围内,安全系数基本大于2.0;碾压和常态混凝土的热力学差异和后期的温度回升对纵缝的开度和接缝灌浆不会产生较大影响;向家坝碾压和常态混凝土的联合筑坝施工方式是成功的,且具有一定的安全富裕度,值得推广;(3)锦屏一级工程反演分析表明,后期发热温升约为5-6℃,短期蓄水过程中混凝土和地基弹性模量约为设计初始值的1.65倍左右,其中混凝土弹模约为36GPa,与试验结果接近;利用反演参数对下一阶段蓄水时坝体变形进行预测,预测值与监测值吻合良好,表明全坝全过程仿真分析方法能较好地仿真分析坝体工作性态,同时也表明坝体应力整体处于弹性工作状态。
[Abstract]:This paper focuses on two problems in the field of hydraulic structure, the real-state simulation of concrete dam and the safety evaluation of joint damming. The joint damming refers to the new technology of the joint construction of the dam body with the RCC and the normal concrete, that is, the dam is in different dam sections, with different elevations from the dam section, and the common concrete and the RCC are in common with the RCC in different areas of the same elevation. The new technology not only speeds up the construction speed of the dam to the dam project, but also saves the project construction cost, which is the progress and innovation of the dam construction idea and the dam construction technology, and has remarkable economic and social benefits. The roller is used. Due to the difference of the thermal and mechanical properties of the two kinds of concrete, the stress of the dam body is different from that of the traditional normal concrete dam and the RCC dam, and the anti-slip stability characteristic of the joint damming dam body can be influenced, However, the current specification is difficult to evaluate. Based on this, this paper compares five evaluation methods of water conservancy standard, power specification, partition safety factor method, direct strength fold subtraction and whole process simulation, and puts forward the concept of partition anti-slip safety factor, and draws the following conclusion: (1) The five methods of evaluation have their advantages and disadvantages. The method is simple in the form of the rigid body limit equilibrium method (the water conservancy standard rigid body limit equilibrium method) and the applicability is strong; the method 2 (partition safety factor method) takes into account the influence of the stress deformation of the dam body, The anti-slip stability safety factor of the dam body under the standard load can be calculated, but the engineering application experience is not currently lacking; and the method 3 (the electric power standard rigid body limit equilibrium method) is used for refining the uncertainty of the material parameters and the uncertainty of the load in a sub-coefficient manner, however, it is not possible to consider that effect of the difference in the stress distribution of the dam body on the stability; the advantage of the method four (direct finite element strength reduction) is that it is possible to simulate the process of the gradual destruction of the structure in the process of reducing the strength of the dam body, but the time-varying effect of the construction period and the running period and the time-varying material of the material can not be taken into consideration; for the angle that the simulation is closer to the real stable state, the strength reduction and subtraction (method 5) is optimal after the whole process is simulated, and the temperature and the stress of the dam can be simulated more truly, The effect of long-term operation on the material weakening is considered on the basis of the deformation time space field, and then the strength reserve coefficient is determined by the strength reduction, and the method is recommended for large and complex engineering problems. (2) The difference of the elastic modulus and the longitudinal joint behavior have no significant influence on the final strength reserve coefficient, but in the course of the progressive instability, the more the concrete elastic modulus of the front area of the dam body is larger than the rear part, the greater the stress of the dam heel, and the more easily the plastic area is extended to the curtain; When the concrete elastic modulus of the front area of the dam body is smaller than the rear part, the difference between the concrete elastic modulus at the front and the rear part is not large. (3) The selection of the intensity criterion is also affected by the calculation result, and the result of partial safety can be obtained by selecting the M-C strength criterion for strength reduction calculation. (4) The influence of the difference of the longitudinal joint behavior on the strength reserve coefficient of the whole dam is not large, but the progressive failure process of the dam body and the safety factor of the stability of the stability of the stability of the stability of the partition are more rapid, and the joint strength is improved to be more favorable for the overall stability of the dam body. The real-state simulation is based on the finite element method, which is a further development of the traditional finite element method, and can simulate the whole process working behavior of the concrete pouring, temperature control, arch, water storage and long-term operation of the first bin, and can obtain the temperature field and the seepage field of each day, Displacement field and stress field. In this paper, the real working behavior of the whole process of the construction of the gravity dam and the arch dam is studied by means of the finite element simulation analysis method. The real working behavior of the whole process of the construction of the gravity dam and the arch dam is studied by combining the measured data and the inversion analysis of the project. The main conclusions are as follows: (1) The simulation analysis method is adopted to study, based on the measured data, the actual working behavior of the analysis engineering can be well inverted; (2) a large temperature gradient is not generated at the interface between the dam and the dam; the maximum temperature and the cooling process of the dam basically meet the anti-cracking requirement; and the stress is basically in a controllable range, the safety factor is basically greater than 2.0; the thermodynamic difference and the later temperature rise of the rolling and normal concrete do not greatly influence the opening degree of the longitudinal joint and the joint grouting; the joint damming construction mode of rolling and normal concrete to the domestic dam is successful and has a certain safety and affluence degree, It is worth to popularize; (3) the inversion analysis of the Jinping first-level engineering analysis shows that the temperature rise of the later stage is about 5-6 鈩，
本文编号：2424122
[Abstract]:This paper focuses on two problems in the field of hydraulic structure, the real-state simulation of concrete dam and the safety evaluation of joint damming. The joint damming refers to the new technology of the joint construction of the dam body with the RCC and the normal concrete, that is, the dam is in different dam sections, with different elevations from the dam section, and the common concrete and the RCC are in common with the RCC in different areas of the same elevation. The new technology not only speeds up the construction speed of the dam to the dam project, but also saves the project construction cost, which is the progress and innovation of the dam construction idea and the dam construction technology, and has remarkable economic and social benefits. The roller is used. Due to the difference of the thermal and mechanical properties of the two kinds of concrete, the stress of the dam body is different from that of the traditional normal concrete dam and the RCC dam, and the anti-slip stability characteristic of the joint damming dam body can be influenced, However, the current specification is difficult to evaluate. Based on this, this paper compares five evaluation methods of water conservancy standard, power specification, partition safety factor method, direct strength fold subtraction and whole process simulation, and puts forward the concept of partition anti-slip safety factor, and draws the following conclusion: (1) The five methods of evaluation have their advantages and disadvantages. The method is simple in the form of the rigid body limit equilibrium method (the water conservancy standard rigid body limit equilibrium method) and the applicability is strong; the method 2 (partition safety factor method) takes into account the influence of the stress deformation of the dam body, The anti-slip stability safety factor of the dam body under the standard load can be calculated, but the engineering application experience is not currently lacking; and the method 3 (the electric power standard rigid body limit equilibrium method) is used for refining the uncertainty of the material parameters and the uncertainty of the load in a sub-coefficient manner, however, it is not possible to consider that effect of the difference in the stress distribution of the dam body on the stability; the advantage of the method four (direct finite element strength reduction) is that it is possible to simulate the process of the gradual destruction of the structure in the process of reducing the strength of the dam body, but the time-varying effect of the construction period and the running period and the time-varying material of the material can not be taken into consideration; for the angle that the simulation is closer to the real stable state, the strength reduction and subtraction (method 5) is optimal after the whole process is simulated, and the temperature and the stress of the dam can be simulated more truly, The effect of long-term operation on the material weakening is considered on the basis of the deformation time space field, and then the strength reserve coefficient is determined by the strength reduction, and the method is recommended for large and complex engineering problems. (2) The difference of the elastic modulus and the longitudinal joint behavior have no significant influence on the final strength reserve coefficient, but in the course of the progressive instability, the more the concrete elastic modulus of the front area of the dam body is larger than the rear part, the greater the stress of the dam heel, and the more easily the plastic area is extended to the curtain; When the concrete elastic modulus of the front area of the dam body is smaller than the rear part, the difference between the concrete elastic modulus at the front and the rear part is not large. (3) The selection of the intensity criterion is also affected by the calculation result, and the result of partial safety can be obtained by selecting the M-C strength criterion for strength reduction calculation. (4) The influence of the difference of the longitudinal joint behavior on the strength reserve coefficient of the whole dam is not large, but the progressive failure process of the dam body and the safety factor of the stability of the stability of the stability of the stability of the partition are more rapid, and the joint strength is improved to be more favorable for the overall stability of the dam body. The real-state simulation is based on the finite element method, which is a further development of the traditional finite element method, and can simulate the whole process working behavior of the concrete pouring, temperature control, arch, water storage and long-term operation of the first bin, and can obtain the temperature field and the seepage field of each day, Displacement field and stress field. In this paper, the real working behavior of the whole process of the construction of the gravity dam and the arch dam is studied by means of the finite element simulation analysis method. The real working behavior of the whole process of the construction of the gravity dam and the arch dam is studied by combining the measured data and the inversion analysis of the project. The main conclusions are as follows: (1) The simulation analysis method is adopted to study, based on the measured data, the actual working behavior of the analysis engineering can be well inverted; (2) a large temperature gradient is not generated at the interface between the dam and the dam; the maximum temperature and the cooling process of the dam basically meet the anti-cracking requirement; and the stress is basically in a controllable range, the safety factor is basically greater than 2.0; the thermodynamic difference and the later temperature rise of the rolling and normal concrete do not greatly influence the opening degree of the longitudinal joint and the joint grouting; the joint damming construction mode of rolling and normal concrete to the domestic dam is successful and has a certain safety and affluence degree, It is worth to popularize; (3) the inversion analysis of the Jinping first-level engineering analysis shows that the temperature rise of the later stage is about 5-6 鈩，
本文编号：2424122
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