大花水RCC双曲拱坝施工期仿真分析
Simulation Analysis of Construction of Dahuashui RCC Double-curvature Arch Dam

摘要 大花水RCC拱坝（H=133m）是世界上在建的最高的碾压混凝土双曲拱坝。大坝在碾压施工过程中，陆续发现了十几条裂缝，并有多条贯穿性裂缝。本文通过对全坝进行施工期全过程仿真分析，对施工过程中出现的裂缝现象进行深入细致的分析，得出施工过程中温度应力过高是导致大坝裂缝产生的重要原因。
Abstract Dahuashui RCC arch dam (H=133m) is the highest RCC double-curvature arch dam under construction in the world. During construction, more than 10 cracks have been found in some area of the dam, among which 6 cracks are perforative. Simulation analysis of construction process of Dahuashui RCC arch dam is carried out in the article. According to analysis of results, thermal stress happened in construction period has exceeded strength of concrete, which is the main cause of cracks.
关键词 RCC双曲拱坝；施工期仿真分析；裂缝成因
Keywords RCC double-curvature arch dam; Simulation analysis of construction process; Cause of cracks
1 前言
1. Foreword
大花水碾压混凝土双曲拱坝最大坝高133m，是目前国内最高的碾压混凝土双曲拱坝。坝顶宽7.0m，坝底拱冠厚23.0m。大花水拱坝于2005年4月底开始碾压，汛前浇至底层灌浆廊道755m高程停工度汛，2005年汛后大坝继续上升，于2006年11月初完成拱坝的碾压混凝土施工。
With a maximum height of 133m, Dahuashui RCC (Roller-Compacted Concrete) dam is currently the highest RCC double-curvature arch dam in China. It is 7.0m wide at the crest and 23.0m thick at the base arch crown. Roller-compacted concrete was started at the end of April in 2005, and it was halted before the flooding season of the same year when the concrete pouring reached the lowest grouting gallery, namely 755m in elevation. The dam concreting resumed after that flooding season and the roller-compacted concrete work was completed at the beginning of November in 2006.
大花水碾压混凝土坝在施工过程中，陆续发现拱坝和左岸重力墩发生的裂缝，根据现场调查，目前共发现裂缝26条，其中拱坝16条，重力墩11条。其中，拱坝裂缝大部分分布在800m高程以上的两岸坝肩，并有多条裂缝为贯穿性裂缝。裂缝的发生对大坝的运行性态将会带来一定影响，对大坝裂缝成因进行深入分析，十分必要。
However, cracks have been detected gradually in the arch dam and the gravity pier on left bank during dam concreting. As revealed from field investigation, a total number of 26 cracks have been discovered, among which 16 were found in the arch dam and 11 in the gravity pier. The majority of the cracks appeared at both abutments of the dam above 800m in elevation, several of them being through cracks. The presence of cracks poses a certain influence upon the performance conditions of the dam. Therefore, it is quite necessary to carry out an in-depth analysis of the causes of such cracks.

华译网北京翻译公司翻译过大量有关大花水RCC双曲拱坝施工期仿真分析的文件资料,Beijing Chinese Translation Service Company has translated many technical documents about Simulation Analysis of Construction of Dahuashui RCC Double-curvature Arch Dam
本文通过研究分析大花水碾压混凝土拱坝施工及观测资料，用全过程仿真分析方法，对施工期的温度场和应力场进行仿真模拟，并对裂缝成因进行深入细致的分析，为大坝的安全运行提供参考。
In this article, whole-process simulation analysis technology has been employed to simulate the temperature field and stress field during construction period based on the construction and observation information and data of Dahuashui RCC arch dam. Besides, a detailed and in-depth analysis has been performed as to the causes of the cracks, thus providing a useful guidance to the safety of the dam operation.
2 计算模型及参数
2. Computation model and parameters
大花水施工期仿真分析采用三维有限元法进行，计算模型包括基础、拱坝和左岸重力坝，考虑了中孔、表孔等坝体结构，模拟了坝体2＃，3＃诱导缝和坝体与左岸重力坝之间的周边缝，共有节点135,751个，单元109,348个，其中坝体单元70,608个，基础单元38,740个，有限元网格如图1。
3-D finite element method was adopted in the simulation of Dahuashui construction. This model involved the base, the arch dam and the gravity pier on the left bank. At the same time, the dam structures such as the middle openings and the top openings have also been considered. The induced cracks 2# and 3#, as well as the peripheral cracks between the dam and the left-bank gravity dam have been simulated. In total, 135,751 nodes and 109,348 elements were generated. The dam body had 70,608 elements and the base 38,740. The finite element mesh is shown in Fig. 1.

图1 大花水仿真分析有限元网格示意图
Fig. 1 Finite Element Mesh of Dahuashui Dam Simulation Analysis
仿真分析基本模拟了大花水拱坝和左岸重力墩的施工过程。计算时段从2005年4月第一仓混凝土浇筑开始直到2007年12月结束。混凝土浇筑的模拟过程中，最小计算步长为0.5天，最大计算步长为3天；混凝土浇筑过程中的长间歇期间，最小计算步长为0.5天，最大计算步长为10天。整个施工期仿真分析过程共计算771步。计算过程中，碾压混凝土的热力学参数如表1和表2。
This simulation has simulated fundamentally the construction process of Dahuashui arch dam and the left-bank gravity pier. The time for computation covers the period starting from April in 2005 when the first bay of concrete was placed to December in 2007 when the placing was completed. In the simulation of concrete placing, the shortest time step was 0.5 day, while the longest time step was 3 days. However, the shortest and longest time steps were changed to 0.5 day and 10 days respectively for the simulation of long break period during concrete placing. In total, 771 steps of computation were involved in the entire simulation process. The mechanical and thermal parameters of RCC for the computation are as shown in Table 1 and 2 respectively.
表1 大花水水电站混凝土力学性能参数
Table 1 Mechanical Parameters of RCC for Dahuashui Hydropower Station
表2 大花水水电站混凝土热学性能参数
Table 2 Thermal Parameters of RCC for Dahuashui Hydropower Station