【作者】 李雪雷；

【导师】 陈健云；

【作者基本信息】 大连理工大学 ， 水工结构工程， 2012， 硕士

【摘要】 目前一批混凝土重力坝在我国西南部兴建与拟建,该地区地质条件复杂,属于地震多发区,且烈度较高,因而研究混凝土重力坝的地震破坏机理进而提出合理的抗震措施成为目前大坝抗震研究的热点。基于此本文开展了以下几点工作：(1)关于重力坝破坏评价指标的研究依然相对薄弱,本文考虑不同地基条件及边界条件,利用Abaqus软件,采用混凝土塑性损伤本构模型,计算了无质量线弹性地基模型下重力坝动力响应；接着考虑将坝体下部部分地基采用DP模型模拟,计算了重力坝动力响应；同时利用无限单元模拟无限地基影响,计算了重力坝动力响应,根据重力坝塑性损伤响应,提出了基于能量耗散的重力坝整体破坏评价指标。(2)地震作用下重力坝损伤开裂成为影响大坝安全的关键因素。根据无质量地基模型下计算得到的坝体损伤部位及损伤程度,提出了不同的抗震配筋形式,利用钢筋混凝土嵌入式模型,计算了不同配筋方案下混凝土重力坝的地震响应,验证了在坝体薄弱部位进行抗震配筋的必要性与实用性。(3)新型复合材料的出现为重力坝抗震加固提供了一种新的途径。本文利用徐世娘团队研制出的超高韧性水泥基复合材料(UHTCC,Ultra High Toughness Cementitious Composites)置换混凝土重力坝表层混凝土,提出了三种方案加固混凝土重力坝抗震薄弱部位。考虑UHTCC单线性硬化本构模型及混凝土塑性损伤耦合本构,模拟了采用UHTCC加固后混凝土重力坝的动力响应并与加固前结果进行了对比验证该材料加固混凝土重力坝的有效性,使用UHTCC能够有效增强混凝土坝的整体安全性,提高大坝的抗震性能。更多还原

【Abstract】 A number of concrete gravity dams are built or proposed in southwest China, where the geological conditions are cmoplex and the earthquake are common, the intensity of which are higher. Therefore it has become the research focus to analyze the seismic failure mechanism of concrete gravity dam and propose reasonable seismic measures.Based on these, several work is carried out as follows in this paper:(1) Damage evaluation about gravity dam is still relatively weak. The dynamic response of concrete gravity dam is simulated under massless linear elastic foundation conditions, plastic-damage model employed, using Abaqus software. And then calculate the reactions considering DP model describing foundation. The infinite elements are adopted to simulate dynamic response of the gravity dam.According to the plastic damage responses, the overall damage evaluation index based on the energy dissipation is presented.(2) Damage and Crack has become a key factor affecting the dam safety under seismic load. According to the damage part and degree under massless foundation model, different forms of seismic reinforcement are presented. Based on the embedded model of reinforced concrete, the seismic responses of concrete gravity dam are calculated under different reinforcement schemes. The consequences verifies the necessity and practicality arranging reinforcemen for seismic resistance at the weak parts of the dam(3) New composite materials provide a new way of strengthening concrete gravity dam. In this paper, the Ultra High Toughness Cementitious Composites (UHTCC), developed by Xu shilang team, is used to replace the surface concrte of dam and then present three schemes to reinforce seismic weak parts of concrete gravity dam. Simple linear hardening constitutive model for UHTCC and concrete plastic damage constitutive model are considered to simulate the dynamic response of concrete gravity dam reinforced with UHTCC. Comparing the results before and after reinforcement, it could be gotten that UHTCC in strengthening dam field is effective, which can enhance the overall safety of the concrete dam and improve the seismic performance of the dam.更多还原