scholarly journals Technique and Practice on Temperature Control and Crack Prevention for RCC Dam at High Altitude in Tibet

Author(s):  
Qian Xiang ◽  
Tao Xiong
2012 ◽  
Vol 238 ◽  
pp. 272-277
Author(s):  
Xiang Dong Xu ◽  
Jin Chao Yue

Yongding RCC gravity dam with large project scale is in the construction all over the year, and the big temperature stress is a key factor for construction quality and progress. The temperature of the RCC dam in typical season with and without control conditions was analyzed by FEM, the temperature situation in typical season of RCC dam was controlled by the embedded cooling water pipes by practical method. Key points in concrete temperature control during high temperature season are found out, the counter measures and issues to be noticed are put forward.


2012 ◽  
Vol 594-597 ◽  
pp. 1979-1982
Author(s):  
Wei Zhou ◽  
Xiang Yang Jing ◽  
Xing Hong Liu

Due to the shortcomings of conventional methods, the temperature control in rapid construction of Guandi dam is less effective. Then improved measures are designed and implemented based on the dynamic control method of pipe cooling, which depends on the real-time adjustment of five factors affecting pipe cooling (beginning time of cooling, lasting time of cooling, water temperature, rate of flow and direction of flow). The monitoring and feedback calculation are conducted. It is found that the newly-designed measures have obvious effect, and that there are no harmful cracks in the whole construction of Guandi dam. The conclusion is that it can effectively solve the problem of temperature control and crack prevention of high RCC dam via these measures, and provide some guide and reference to other similar projects.


2012 ◽  
Vol 170-173 ◽  
pp. 2110-2114
Author(s):  
Yuan Chun Xia ◽  
Dong Fei Lin

Yeywa hydropower station RCC dam is located in the torrid zone of Asian, During the construction period, it meet Technical problem of temperature control in hot season. We can utilize the peculiarity of RCC that has a slow temperature rise due to hydration heat and a low early strength, according to analyse the blending and concreting procedure of RCC, adopt comprehensive and effective temperature control method, such as confirm concrete mix, control the temperature of raw material and RCC out of the batch plant, prevent temperature rise during transporting and concreting, setting joint to avoid structural crack and temperature crack. From Yeywa hydropower station RCC dam construction finished to now, no dangerous crack is detected, It accumulate experiences for RCC dam construction in high temperature place.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Zhenhong Wang ◽  
Li Tao ◽  
Yi Liu ◽  
Jiang Yunhui

The focus on the development of China’s vast hydropower resources has shifted to Tibet and other plateau regions. These areas are high-altitude regions whose basic climatic characteristics are as follows: dry climate, significant differences in daily temperature, and strong solar radiation. If a dam is built under such special climate conditions, specific and strict temperature control and crack prevention measures should be taken. Therefore, this study explores the temperature control standards, as well as temperature control and crack prevention measures, for concrete in high-altitude regions using three-dimensional finite element methods and based on the concrete gravity dam in Tibet in combination with the characteristics of material properties that are disadvantageous to temperature control and crack prevention. The temperature drop process can be optimized in time, and the temperature drop rate can be controlled to prevent excessive scale and temperature drop rates. Moreover, the temperature gradient can be spatially optimized, and thus, the differences in foundation temperatures, upper- and lower-layer temperatures, and internal and external temperatures can also be reduced. The research shows that the recommended temperature control and crack prevention measures can effectively reduce temperature stress. This study has a significant value as a reference for similar projects in high-altitude regions.


2018 ◽  
Vol 10 (1) ◽  
pp. 168781401775248 ◽  
Author(s):  
Bingqi Li ◽  
Zhenhong Wang ◽  
Yunhui Jiang ◽  
Zhenyang Zhu

Temperature cracks commonly occur during mass concrete construction. Research shows that changes in temperature and peripheral constraints mainly cause crack formation in concrete. Engineers who lack experience often build structures prone to concrete cracks. Dams built in the high-altitude areas of Tibet are examples of such structure. Climatic conditions, such as large temperature variation and strong solar radiation, disrupt temperature control and crack prevention in concrete. In this study, we explored the measures for temperature control and crack prevention that are suitable for concrete structures, especially those built in high-altitude areas with large temperature variation and strong constraint zones. The study was performed in a steep slope dam section and stilling basin in Tibet. The finite element method was used to guide the engineering construction in the area. These methods could be applied to the construction of similar projects in other high-altitude areas.


2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Zhenhong Wang ◽  
Yi Liu ◽  
Guoxin Zhang ◽  
Shuping Yu

There are unprecedented difficulties in building concrete gravity dams in the high altitude province Tibet with problems induced by lack of experience and technologies and unique weather conditions, as well as the adoption of construction materials that are disadvantageous to temperature control and crack prevention. Based on the understandings of the mentioned problems and leveraging the need of building gravity dam in Tibet, 3D finite element method is used to study the temperature control and crack prevention of the dam during construction. The calculation under recommend temperature control measures and standards shows that the height and number of simultaneous cooling zone have the more obvious influencers on concrete stress; therefore, it is suggested to increase the height of simultaneous cooling zone to decrease the stress caused by temperature gradient of adjoin layers so as to raise the safety level of the whole project. The research methods and ideas used on this project have significant values and can be taken as references in similar projects in high altitude regions.


1994 ◽  
Vol 144 ◽  
pp. 365-367
Author(s):  
E. V. Kononovich ◽  
O. B. Smirnova ◽  
P. Heinzel ◽  
P. Kotrč

AbstractThe Hα filtergrams obtained at Tjan-Shan High Altitude Observatory near Alma-Ata (Moscow University Station) were measured in order to specify the bright rims contrast at different points along the line profile (0.0; ± 0.25; ± 0.5; ± 0.75 and ± 1.0 Å). The mean contrast value in the line center is about 25 percent. The bright rims interpretation as the bases of magnetic structures supporting the filaments is suggested.


Sign in / Sign up

Export Citation Format

Share Document