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2. Application of Drainage Technique to Water Diversion Tunnels in Water-Rich Karst Area.
- Author
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Jun Yao, Yuan Wang, and Di Feng
- Subjects
- *
WATER tunnels , *DRAINAGE , *WATER diversion , *TUNNELS , *WATER pressure , *KARST , *DIVERSION structures (Hydraulic engineering) , *WATER table - Abstract
In water-rich karst area, the lining structure of diversion tunnels is prone to cracking and gushing water problems under high water pressure, so water drainage design is often adopted for these diversion tunnels, that is, to drill holes on the lining structure and install drainage equipment to lower the external water pressure of the lining, therefore, accurately calculating the external water pressure of the lining is a very important work for the safety of the lining structure of tunnels. Based on the method of equivalent permeability coefficient, this paper regarded the drainage capacity of drainage equipment installed on the lining and the permeability of lining itself as a whole, and used the virtual equivalent permeability coefficient of the lining to describe it; then, this paper proposed a method for determining the equivalent permeability coefficient of lining and used it to analyze the drainage effect. Main conclusions of this paper are: 1) By designing tests for the drainage model of the tunnel drainage equipment and theoretically analyzing the seepage field of hydraulic tunnel, the equivalent permeability coefficient of the lining was determined and its accuracy was verified via numerical calculation; 2) Analytical calculation results and numerical simulation results of the tunnel were analyzed, and their conclusions about the effect of drainage capacity on the external water pressure of the lining were consistent; 3) The tunnel drainage design is an effective measure to reduce the external water pressure of the lining, the pressure reduction effect is obvious when k<1×10-6, and the groundwater level around the tunnel could be reduced at the same time. This paper provides a useful evidence for the design of high-pressure water diversion tunnels. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
3. Experimental Study on Carbonation of Cement-Based Materials in Underground Engineering.
- Author
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Zheng, Jun, Zeng, Gang, Zhou, Hui, and Cai, Guanghua
- Subjects
CARBONATION (Chemistry) ,TUNNELS ,TUNNEL lining ,MORTAR ,STRUCTURAL stability ,SQUARE root ,ENGINEERING - Abstract
The corrosive water environment has a decisive influence on the durability of a diversion tunnel lining. In this paper, the effects of carbonation on cement-based materials in water-immersion and saturated-humidity environments were studied by increasing the CO
2 concentration. The results show that under conditions of water-immersion and saturated humidity, the color of the non-carbonation region is dark, while the carbonation region is gray, and the color boundary is obvious. However, in an atmospheric environment, there is no zone with a dark color and the color boundary is not obvious. In a saturated-humidity environment, the carbonation depth increases over time and changes greatly, and its value is about 16.71 mm at 200 days. While in a water-immersion environment, the carbonation depth varies little with time and the value is only 2.31 mm. The carbonation depths of cement mortar samples in different environments generally follow a linear relationship with the square root of time. The carbonation coefficient in a saturated-humidity environment is more than nine times that in the water-immersion environment. In a water-immersion environment, the carbonation causes a large loss of calcium in cement-based materials, and their Ca/Si ratio obviously decreases. The calcium silicon ratio (Ca/Si) of cement-based materials in a water-immersion environment is 0.11, which is much less than 1.51 in a water-saturated environment and 1.49 in an atmospheric environment. In a saturated-humidity environment, the carbonation only reduces the pH of the pore solution in the carbonation region, and the structural stability of cement-based materials is not degraded. The number of pores of all radii after carbonation in a water-immersion environment exceeds that in a saturated-humidity environment, and the total pore volume and average pore radius in a water-immersion environment are also larger than in a saturated-humidity environment, so the water-immersion environment accelerates the development and expansion of pores. The research results can provide some theoretical and technical support for the design, construction, and safe operation of diversion tunnel linings. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
4. 基于控制图的钻爆法引水隧洞超挖影响因子研究.
- Author
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乔树勋
- Abstract
Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
5. Damage analysis and safety control of surrounding rock around peripheral hole of diversion tunnel.
- Author
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Yang, Yumin, Jiang, Nan, Zhou, Chuanbo, Meng, Xianzhong, Zhu, Bin, and Cai, Zhongwei
- Subjects
- *
STRESS waves , *FREE surfaces , *BLAST waves , *PREDICTION models , *BLASTING - Abstract
• Combined with field test and numerical simulation, the rock damage characteristics around peripheral hole are fully analyzed. • The influence of explosive spacing, blasthole spacing and smooth blasting layer thickness on different damage indexes of rock mass is analyzed, and the influence of boundary conditions is discussed. • Considering the influence of explosive spacing and blasthole spacing, a mathematical model is established firstly to predict the rock damage range and applied to engineering practice. • The research method in this paper provides a solution to similar engineering problems. The control of overbreak in blasting excavation is a significant technical challenge and a subject of extensive research in the field of engineering. This study examines the damage characteristics of the surrounding rock in a tunnel section through blasting test and numerical simulation conducted as part of the San Gavan diversion tunnel project in Peru. The orthogonal test of peripheral holes under the influence of explosive spacing, blasthole spacing and smooth blasting layer thickness was designed to analyze the characteristics of rock damage under different parameter combinations and the influence of various factors on rock damage. Based on the USBM formula, this paper deduces a mathematical model considering blasthole spacing and explosive spacing to predict the rock damage range. The main conclusions are as follows: on the tunnel section, the average damage range of vault and arch springer is slightly larger than that of spandrel and haunch. For a single blasthole, the rock damage range in different sections is: explosive > air > stem, and the degree of rock damage at the bottom of blasthole is the highest. Smooth blasting layer thickness has a significant effect on rock damage rate on the side of non-reflect boundary. When smooth blasting layer thickness is 45 cm and 55 cm, the boundary conditions of numerical model have a significant effect on the rock damage. The reflection of blasting stress wave on the free surface leads to the further increase of rock damage range. The blasthole spacing and explosive spacing have a significant effect on rock damage range on the side of non-reflect boundary, and both show a negative correlation. Based on the prediction model of rock damage, the combination of peripheral hole parameters satisfying the standard is obtained, which provides guidance for blasting design. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. 引水隧洞表观缺陷智能检测与规律分析.
- Author
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黄会宝, 谢辉, 马芳平, 彭涛, 李佳龙, and 彭望
- Abstract
Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2023
- Full Text
- View/download PDF
7. 某水电站导流洞出口围堰选型及施工技术.
- Author
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方 琳, 赵旭峰, 孙家波, 李长明, and 陈 诚
- Abstract
The cofferdam is a temporary water retaining structure built to protect the foundation pit in the construction of hydraulic engineering. Its layout has great influence to the flood safety, project progress and cost. Relying on the diversion tunnel project of a hydropower station, this paper firstly optimized the design of the cofferdam type at the outlet of the diversion tunnel, and then compares various construction schemes such as earth rock cofferdams, concrete cofferdams, stoplogs gate, and concrete cutoff walls. The cofferdam scheme was designed, and the construction technology and construction scheme of the cofferdam were systematically expounded. The analysis results show that the cofferdam at the exit of the diversion tunnel uses the stoplogs gate type to control the flood season, which meets the requirements of the project safety flood control, significantly reduces the amount of cofferdam engineering and the project cost, and has strong technical feasibility. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
8. Zaramag HPP-1 on the River Ardon in the Republic of North Ossetia — Alania: Preoperational Program of Hydraulic Structure Safety Tests and its Implementation.
- Author
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Kasatkin, N. V., Petrov, V. V., and Konikh, G. S.
- Abstract
Zaramag HPP-1 is an extremely challenging project, unique in its design and in head. Prior to start-up, the hydraulic structures are subjected to a multistage testing program at different heads. The first test results are presented in this paper. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
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9. 引汉济渭引水隧洞穿椒溪河段突涌水数值模拟.
- Author
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李立民, 刘国平, 许增光, and 肖 瑜
- Abstract
Copyright of Yellow River is the property of Editorial Board of Yellow River and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2019
- Full Text
- View/download PDF
10. 流冰对引水隧洞撞击破坏力学特性数值分析与验证.
- Author
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贡 力, 李雅娴, and 靳春玲
- Abstract
In high latitude region of western China, the environment is in harsh condition that it is cold and dry in winter and has long ice period, which causes many water resource problems. In order to relieve the serious water shortage condition in cold and dry region, a large number of long distance water diversion projects were established to improve the water resource condition, such as increasing farm irrigation, human and animal drinking. While the ice damage occurs frequently under severe ice conditions in cold and dry region, especially in ice period in winter and thawing period in spring, it is easy to form drift ice with different velocities, different plan sizes and different thicknesses, which produces different extrusion forces or impact forces to damage tunnel lining, causing project failure. The failure project could not realize the original planning and construction goal, giving rise to the water allocation pressure. The water allocation would cause water shortage which influences diversion irrigation and farming production in spring. Based on the intense researches on the collision simulation problem of the interaction between drift ice and diversion tunnel, this paper used the symmetric penalty function in the finite element contact-impact algorithm to conduct the theoretical study on collision simulation problem between drift ice and water diversion tunnel. ANSYS/LS-DYNA was adopted as the platform to establish tunnel model and drift ice model. LS-DYNA SOLVER was used as the solver to solve and analyze the damage degrees of drift ice on tunnel. The physical model tests were conducted to verify and reveal the impact damage mechanism of drift ice on diversion tunnel. The physical model was constructed by the geometric scale of 28, which is the ratio of the experiment facility to the prototype in the test. The results show that tunnel lining surface will form varying degrees of deformation and failure when the tunnel lining is impacted by the drift ice with different velocities, different plane sizes and different thicknesses. It is also discovered that the impact stress increases with the flow velocity and their relationship presents linear variation. The impact stress also increases with the drift ice’s plane size and their relationship presents nonlinear variation. The impact stress increases with the drift ice thickness when the drift ice thickness is less than 0.5 m. While the drift ice thickness is greater than 0.5 m, the maximum stress value shows little change. The relationship between drift ice’s plane size and maximum stress shows approximately linear variation. Meanwhile, the software simulation and test observation results are almost the same. The impact of drift ice on the tunnel lining would cause the deformation of lining, but the deformation has little influence on the tunnel stability. The drift ice’s long time erosion would cause the tunnel lining surface to fall off, and further break the strength and stability of the tunnel structures. The study supplies theoretical support and technical guarantee for water diversion project security in cold and dry region of western China. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
11. Research on Tunnel Boring Machine Tunnel Water Disaster Detection and Radar Echo Signal Processing.
- Author
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Lu, Gaoming, Ma, Yan, Zhang, Qian, Wang, Jianfei, Du, Lijie, and Hao, Guoqing
- Subjects
RADAR signal processing ,WATER tunnels ,GROUND penetrating radar ,RADAR equipment ,RADAR interference ,TUNNELS ,SYNTHETIC apertures ,RADAR antennas - Abstract
This study focused on the detection of water inrush in tunnels excavated by full-section hard rock tunnel boring machines (TBMs) and employed ground penetrating radar methods for conducting research on radar signal processing algorithms. The research demonstrates that conventional techniques are inadequate for eliminating the interference of TBM equipment on radar signal propagation. This study employs a radar antenna array method for signal transmission, utilizing a wavelet double-threshold filtering algorithm and wave propagation theory to suppress clutter. These methods exhibit strong signal reception capabilities and are effective in eliminating 13.1% of the direct wave components. The adoption of a novel, efficient radar signal imaging algorithm simplifies the imaging process. Results of verification indicate that the synthetic aperture algorithm, enhanced with cross-correlation calculation, yields the optimal imaging effect. This investigation, which was conducted in conjunction with the construction of a diversion tunnel in a specific region, has confirmed the applicability of the ground penetrating radar method for the detection of water inrush in TBM tunnels by conducting a comparative analysis of the direct wave removal algorithm and the integration of the optimal imaging algorithm. The innovative application of ground penetrating radar within TBM tunnels, along with a targeted technology to mitigate signal interference from metal equipment, has led to the selection of an appropriate algorithm for both signal processing and imaging. This approach offers a novel solution for the detection of water source disasters in TBM tunnels. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
12. Study on Hydraulic Characteristics of Horizontal and Vertical Cross Inlet
- Author
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Zhang, Mengzhen, Chen, Ming, Sun, Jiyang, Wu, Bin, Chen, Qingsheng, di Prisco, Marco, Series Editor, Chen, Sheng-Hong, Series Editor, Vayas, Ioannis, Series Editor, Kumar Shukla, Sanjay, Series Editor, Sharma, Anuj, Series Editor, Kumar, Nagesh, Series Editor, Wang, Chien Ming, Series Editor, Cui, Zhen-Dong, Series Editor, Mei, Guoxiong, editor, Xu, Zengguang, editor, and Zhang, Fei, editor
- Published
- 2024
- Full Text
- View/download PDF
13. Investigation on Disaster Mechanism of Diversion Tunnel Induced by Gripper TBM in Hydrokarst Erosion Stratum and Engineering Measures.
- Author
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Yang, Tengtian
- Subjects
TUNNELS ,TUNNEL design & construction ,SEISMIC waves ,GEOLOGICAL formations ,EROSION ,ENGINEERING ,WATER softening - Abstract
In gripper tunnel boring machine (TBM) tunneling through complex geological formations, the safe and efficient recovery from large-scale collapses remains a formidable challenge. In this study, we investigate the causes of a 1246 m
3 collapse that occurred during the gripper TBM tunneling in the diversion tunnel in Xinjiang, China. Various techniques including TSP seismic waves, CFC advanced water exploration, laboratory point load tests and packer permeability tests were employed for thorough research. The examination discloses that the water softening in biotite-quartz schist in fractured zones contributes significantly to the loosening and dislocation of rock layers along joints. The gripper TBM's cutterhead exacerbates this process through cutting action and vibrations, causing large-scale instability and eventual rock mass collapse. To tackle this engineering problem, we propose a three-step treatment scheme comprising "Reinforcement-Backfill-Re-excavation". Furthermore, we propose a technique to handle TBM collapses by creating a "protective shell" within the cavity. The safety and feasibility of these proposed solutions were thoroughly validated through numerical simulations. Also, we utilized the Hoek-Brown theory and Rostami prediction formula to establish recommended values for the total thrust and total torque of the TBM during the collapsed section. The proposed treatment scheme and estimated parameters were successfully applied, resulting in a comprehensive solution from collapse handling to tunneling. This study offers valuable details on effectively managing large-scale collapses in gripper TBM tunneling, which can be useful for similar tunnel engineering and improve safety and efficiency. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
14. Geophysical exploration for a long deep tunnel to divert water from the Yangtze to the Yellow River, China.
- Author
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An, Zhiguo, Di, Qingyun, Wu, Faquan, Wang, Guangjie, and Wang, Ruo
- Subjects
WATER diversion ,GEOPHYSICAL prediction ,GEOPHYSICAL surveys ,MAGNETOTELLURIC prospecting - Abstract
Copyright of Bulletin of Engineering Geology & the Environment is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2012
- Full Text
- View/download PDF
15. Research on hydraulic–electric interference and optimisation of multi‐turbine hydropower system based on the dual control mode.
- Author
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Duan, Chen, Minglu, Zhang, Changbing, Zhang, Mengjiao, Yang, Cheng, Mao, and Chunhe, Shen
- Abstract
Aiming at the complex hydraulic and electrical interference, as well as the stability of the hydropower plant that one diversion tunnel supplies water to multiple turbines, a high‐order coupling model based on the dual control mode of the speed and excitation regulation is developed. Some scenarios, involving the hydraulic interference law, the effect of partial load rejection on the stability and dynamic characteristics of the units, and the optimisation of the power system stabiliser (PSS), are investigated. It is found that the change of the guide vane opening (or power) of one of the units causes the water hammer in its spiral case and penstock, and the water level fluctuation in the surge chamber. Besides, hydraulic disturbances suffered by other units are mainly caused by water level fluctuation in the surge chamber, rather than directly from the water hammer. The results demonstrate that the unit wiring of the generator and transformer is better than the expansion unit wiring in terms of the dynamic characteristics. In addition, PSS not only can suppress low‐frequency oscillations, but also affect the hydraulic transition process, and the improved PSS2B‐proportional–integral–derivative can increase the positive damping, and more effective in suppressing system oscillations. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
16. Excavation and Construction Technology of Diversion Tunnel under Complex Geological Conditions.
- Author
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He, Na and Zhang, Xianggang
- Subjects
EXCAVATION ,TRAVEL time (Traffic engineering) ,WATER tunnels ,SHAFTS (Excavations) ,WATER diversion ,ROCK music - Abstract
During the construction of a diversion tunnel, geological problems often include faults, fragile strata, hard rock formations, karst landforms, etc., which may have adverse effects on the excavation and construction of the diversion tunnel. Based on the analysis of the engineering overview, this study designed a new construction technology for the excavation of water diversion tunnels in hard rock layers and high-karst areas. Based on tunnel seismic prediction (TSP) technology to achieve advanced geological prediction, combined with actual geological conditions, construction difficulties are analyzed. Then, detection technology is used to collect two-way travel time, amplitude, and waveform data. By processing and analyzing the detection image, the spatial orientation and length of the main tunnel during the construction of the diversion tunnel are calculated. After completing the construction ventilation and wind, water, and electricity layout, the excavation construction procedure is designed. In the specific excavation design, the tunnel curtain excavation technology, tunnel body excavation and support technology, excavation grouting technology, important unfavorable geological tunnel section excavation technology, upper/lower flat section excavation technology, upper/lower curved section excavation technology, and vertical shaft section excavation technology were elaborated. Finally, a plan was made for the reuse process of slag material and a construction quality control system was established. During the testing process, it was found that the antidamage coefficient of the side wall was above 0.9 after using the technology described in this article. Therefore, it indicates that the excavation construction technology designed in this article can ensure the support capacity of the side wall of the diversion tunnel, which is suitable for the excavation of the main tunnel during the construction of the diversion tunnel. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
17. Solving problem of encountering a huge cavern in a TBM drive for water diversion tunnel project in Northern Thailand.
- Author
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Harnpattanapanich, Thanu, Phienwej, Noppadol, Rodploy, Jitaphol, Monthanopparat, Nantapol, Tanomtin, Chawalit, and Kongdang, Koson
- Subjects
WATER tunnels ,WATER diversion ,TUNNEL design & construction ,CAVES ,PROBLEM solving ,GROUT (Mortar) ,BORING & drilling (Earth & rocks) ,MINE water - Abstract
A huge cavern in a zone of thrusted and sheared clastic sedimentary rocks was encountered during drill and blast (D&B) and tunnel boring machine (TBM) excavation of water transfer tunnel in Thailand. The cavern floor made of thick and loose pile of fallen rock blocks hampered the advance of the TBM through it. Because the size of the cavern was large (50 m × 40 m) and the extent of the thickness of the pile of rock blocks could not be precisely determined, the adopted ramification was to solidify a zone of loose rock fragments around the tunnel alignment. This measure is to allow a safe TBM excavation passing the cavern and ensure the long‐term function of the segmented concrete‐lined tunnel to convey water without problem of loss from subsidence damage. The scheme of the solidification consisted of staged grouting that began with polyurethane (PU) foam grouting to form a bottom barrier of the intended cement grout zone. It was followed large void filling by flowable concrete and then cement injection for the remaining smaller voids. The work that took 8 months to complete started with the excavation of a bypass adit to the front of TBM cutterhead as an access to the cavern and the installation of dewatering and ventilation systems to the cavern so that the grouting work could be made. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
18. Study on Mechanical Properties of Surrounding Rock and Combined Stress of Composite Lining in the Diversion Tunnel.
- Author
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Jiang, Yan, Wang, Wenlong, Yang, Guanghua, Yue, Jinchao, and Huang, Yibin
- Subjects
ROCK deformation ,TUNNEL lining ,ROCK properties ,REINFORCED concrete ,FINITE element method ,SOUND waves - Abstract
To determine the mechanical properties of the rock mass in the Nansha Branch, three in-situ tests (on-site pressure plate, borehole TV and acoustic wave, and borehole deformation methods) were carried out. Based on the deformation characteristics of the rock mass, the finite element numerical method is used to study the combined stress of the composite lining in the diversion tunnel. The results demonstrate that the deformation modulus values are similar by comparing them to tests of the pressure plate and borehole deformation method. It shows the accuracy and reliability of the deformation modulus obtained by the borehole deformation method. In addition, the deformation modulus of the borehole deformation method and wave velocity were fitted to obtain a power function relationship. The deformation modulus of the pelitic siltstones was estimated. After the Nansha Branch tunnel is filled with water, the maximum principal stress of the pipe piece is 1.953 Mpa in tensile stress, located at the outside of the waist on both sides of the pipe piece. The maximum principal stress of the reinforced concrete lining is 5.407 Mpa, located at the top and bottom inside. The maximum principal stresses have exceeded the standard tensile strength of both the pipe piece and reinforced concrete and are vulnerable to cracking. Special attention should be paid to the deformation of the above parts with regard to long-term operation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
19. Stability Analysis of Surrounding Rock in the Diversion Tunnel at the Xulong Hydropower Station based on RFPA 3D and Microseismic Monitoring.
- Author
-
Qian, Hongjian, Tan, Zhou, and Li, Biao
- Subjects
ROCK analysis ,WATER power ,ROCK bursts ,ACOUSTIC emission ,FAILURE mode & effects analysis ,EXCAVATION - Abstract
To study the surrounding rock stability of the excavated geologically weak section of the #2 diversion tunnel in the Xulong Hydropower Station, a quasi-3D numerical model was built using the Realistic Failure Process Analysis (RFPA
3D ) system to simulate the damage and failure process consisting of crack initiation, growth, and penetration in the rock mass after tunnel excavation, and reveal the instability failure mechanism inside the rock mass. Moreover, the microseismic monitoring technology was employed to delineate potential danger areas in the surrounding rock of the tunnel and explore possible instability failure modes. Results indicate that the surrounding rock of the tunnel profile failed as different degrees during the excavation process, most obviously near the vault and corners of the side wall, where tensile failure predominated. As the excavation proceeded, microseismic events increased gradually at the vault and corners of the side wall, and the energy from acoustic emissions accumulated steadily, thus raising the possibility of collapse and rock bursts in this area. The research results can provide technical support for the construction of the diversion tunnel project in the Xulong Hydropower Station and serve as a guide for the construction of similar geologically weak underground projects. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
20. Problem Analysis and Geotechnical Study at Sengulam Augmentation Scheme
- Author
-
Michel, Sinai, Nimmymol, K. A., Zacharia, Jiya, Nazeer, Nazrin, di Prisco, Marco, Series Editor, Chen, Sheng-Hong, Series Editor, Vayas, Ioannis, Series Editor, Kumar Shukla, Sanjay, Series Editor, Solari, Giovanni, Series Editor, Sharma, Anuj, Series Editor, Kumar, Nagesh, Series Editor, Wang, Chien Ming, Series Editor, Das, Bibhuti Bhusan, editor, and Neithalath, Narayanan, editor
- Published
- 2019
- Full Text
- View/download PDF
21. Construction schedule simulation of a diversion tunnel based on the optimized ventilation time
- Author
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Wang, Xiaoling, Liu, Xuepeng, Sun, Yuefeng, An, Juan, Zhang, Jing, and Chen, Hongchao
- Subjects
- *
TUNNEL design & construction , *TUNNEL ventilation , *MATHEMATICAL optimization , *SIMULATION methods & models , *MOMENTUM (Mechanics) , *GEOGRAPHIC information systems , *METHANE - Abstract
Former studies, the methods for estimating the ventilation time are all empirical in construction schedule simulation. However, in many real cases of construction schedule, the many factors have impact on the ventilation time. Therefore, in this paper the 3D unsteady quasi-single phase models are proposed to optimize the ventilation time with different tunneling lengths. The effect of buoyancy is considered in the momentum equation of the CO transport model, while the effects of inter-phase drag, lift force, and virtual mass force are taken into account in the momentum source of the dust transport model. The prediction by the present model for airflow in a diversion tunnel is confirmed by the experimental values reported by Nakayama [Nakayama, In-situ measurement and simulation by CFD of methane gas distribution at a heading faces, Shigen-to-Sozai 114 (11) (1998) 769–775]. The construction ventilation of the diversion tunnel of XinTangfang power station in China is used as a case. The distributions of airflow, CO and dust in the diversion tunnel are analyzed. A theory method for GIS-based dynamic visual simulation for the construction processes of underground structure groups is presented that combines cyclic operation network simulation, system simulation, network plan optimization, and GIS-based construction processes’ 3D visualization. Based on the ventilation time the construction schedule of the diversion tunnel is simulated by the above theory method. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
22. Support capacity estimation of a diversion tunnel in weak rock
- Author
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Özsan, A. and Başarır, H.
- Subjects
- *
DIVERSION structures (Hydraulic engineering) , *TUNNELS - Abstract
This paper presents the results of the support capacity estimation for the diversion tunnel of the Urus¸ dam site in highly weathered tuff and weak zone. Tunneling in weak rock requires some special considerations, since misjudgment in support design results in costly failures. There are several ways of estimating rock support pressure and selecting support. However, all systems suffer from their characteristic limitations in achieving objectives. Thus, it is more useful to use different methods for estimating support pressure and type of support. The support pressure pi was established by three different methods. These methods are the (1) empirical methods based on rock mass rating (RMR) and rock mass quality index (Q-classification systems), (2) ground support interaction analysis (GSIA) and (3) numerical methods, namely, Phase2 finite element (FEM) program. Rock masses were characterized in terms of RSR, RMR, Q-system and GSI. Drill-core samples were tested in the rock mechanics laboratory to determine physico-mechanical properties. Rock mass strength was estimated by empirical methods. Finally, the required support system is proposed and evaluated by different methods in the highly weathered tuff and weak zone of the diversion tunnel. [Copyright &y& Elsevier]
- Published
- 2003
23. Recommended Conditions for the Operation of Vortex Spillways
- Author
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Gur’ev, A. P., Khanov, N. V., and Abidov, M. M.
- Published
- 2021
- Full Text
- View/download PDF
24. Experimental Study on Carbonation of Cement-Based Materials in Underground Engineering
- Author
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Jun Zheng, Gang Zeng, Hui Zhou, and Guanghua Cai
- Subjects
diversion tunnel ,corrosion ,cement-based materials ,carbonation ,experimental study ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
The corrosive water environment has a decisive influence on the durability of a diversion tunnel lining. In this paper, the effects of carbonation on cement-based materials in water-immersion and saturated-humidity environments were studied by increasing the CO2 concentration. The results show that under conditions of water-immersion and saturated humidity, the color of the non-carbonation region is dark, while the carbonation region is gray, and the color boundary is obvious. However, in an atmospheric environment, there is no zone with a dark color and the color boundary is not obvious. In a saturated-humidity environment, the carbonation depth increases over time and changes greatly, and its value is about 16.71 mm at 200 days. While in a water-immersion environment, the carbonation depth varies little with time and the value is only 2.31 mm. The carbonation depths of cement mortar samples in different environments generally follow a linear relationship with the square root of time. The carbonation coefficient in a saturated-humidity environment is more than nine times that in the water-immersion environment. In a water-immersion environment, the carbonation causes a large loss of calcium in cement-based materials, and their Ca/Si ratio obviously decreases. The calcium silicon ratio (Ca/Si) of cement-based materials in a water-immersion environment is 0.11, which is much less than 1.51 in a water-saturated environment and 1.49 in an atmospheric environment. In a saturated-humidity environment, the carbonation only reduces the pH of the pore solution in the carbonation region, and the structural stability of cement-based materials is not degraded. The number of pores of all radii after carbonation in a water-immersion environment exceeds that in a saturated-humidity environment, and the total pore volume and average pore radius in a water-immersion environment are also larger than in a saturated-humidity environment, so the water-immersion environment accelerates the development and expansion of pores. The research results can provide some theoretical and technical support for the design, construction, and safe operation of diversion tunnel linings.
- Published
- 2022
- Full Text
- View/download PDF
25. Efficiency of Diversion Tunnel No. 3 of the Rogun HPP: Operating Experience
- Author
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Shakirov, R. R. and Kupriyanov, V. P.
- Published
- 2021
- Full Text
- View/download PDF
26. Temperature-Stress Analysis of Rock-Shotcrete Structure under High Temperature Cooling Effect.
- Author
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Hui Su, Min Liang, Baowen Hu, ZhouXiang Xuan, Yue Xin, and Yi Zhu
- Subjects
TEMPERATURE effect ,HIGH temperatures ,GEOTHERMAL engineering ,ROCK deformation ,ACCELERATION (Mechanics) ,MECHANICAL stress analysis - Abstract
Take the diversion tunnel located in geothermal area as engineering background, the coupled temperature-stress analysis of rock-shotcrete structure with high temperature was performed under immersion action of cold water. The Physical and simulation experiment show that temperature evolution of rock-shotcrete structure can be classified into three stages, which are initial rapid decay stage, deceleration decay stage and the equilibrium stage; The stress simulation shows that the sharp change of stress will occur in the shotcrete layer during the first stage, and maximum principal stress is mainly manifested as tensile stress, which will easily lead to tensile failure of the shotcrete layer; the displacement simulation shows that the rock-shotcrete structure takes on overall shrinkage deformation in each temperature stage, and it is most obvious for shotcrete layer. The deformation of rock plate will not stop until temperature reaches stable state. Such kind of deformation law will weaken constraint on the shotcrete material, and therefore lead to stress relief in the shotcrete layer. [ABSTRACT FROM AUTHOR]
- Published
- 2019
27. Numerical Evaluation of Empirically Suggested Support System for the Diversion Tunnels at Diamer Basha Dam Project, Pakistan.
- Author
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Rehman, Hafeezur, Naji, Abdul Muntaqim, Ali, Wahid, Mukhta, Hafiz Muhammad, and Mandokhail, Saeed Ullah Jan
- Subjects
ROCK deformation ,TUNNELS ,AXIAL stresses ,BUILDING sites ,TUNNEL design & construction ,ROCK bolts - Abstract
During the design of the tunnel in rocks, inadequate geological and geotechnical data of the construction site is a way of life. Due to this insufficiency of data, the empirical systems for rock-mass are still required for the underground excavation design. The characterization of rock mass followed by classification is an essential part of the initial support design using RMR and Q systems. In this research, these systems are used for the classification of rock mass along the diversion tunnel of a hydropower project in Pakistan. The GSI system is used for the calculation of well-known failure criteria constants. Rock mass is characterized and classified into three geological units along the tunnel route, based on seven number of bore holes, drilled in this route. These rock mass quality values are used for the deformation modulus calculation. The in situ stresses are also calculated statistically, using the available empirical equations. The empirical support determined from the two systems is evaluated numerically, using FLAC2D. The results of numerical modelling indicate that the support suggested by empirical approaches are appropriate. The results are shown in term of critical strain, thrust-bending moment interaction diagram, and axial stresses in rock bolts. Although the highest critical strain value is 0.00058 for geotechnical unit 2, however, this deformation is within the control range. [ABSTRACT FROM AUTHOR]
- Published
- 2019
28. Process Equipment of the Zaramag HPP-1
- Author
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Ryabov, A. E., Ivanenko, E. O., and Rybets, A. I.
- Published
- 2020
- Full Text
- View/download PDF
29. Alternative Solutions for the Energy Dissipation of Idle Discharges at the Rogun HPP
- Author
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Gur’ev, A. P., Kozlov, D. V., Khanov, N. V., Abidov, M. M., and Safonova, N. A.
- Published
- 2020
- Full Text
- View/download PDF
30. Seepage analysis of a diversion tunnel with high pressure in different periods: a case study.
- Author
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Wang, Tao, Hu, Wanrui, Wu, Hegao, Zhou, Wei, Su, Kai, and Cheng, Long
- Subjects
SEEPAGE ,HYDROELECTRIC power plants ,FINITE difference method ,HYDROELECTRIC power plant design & construction - Abstract
The seepage field for a diversion tunnel with high pressure in the Coca Codo Sinclair hydroelectric project is investigated using finite difference algorithms during periods of construction completion, operation and overhaul. The transient seepage calculation using FLAC3Dis verified by a one-dimensional confined flow problem. The equivalent permeability coefficient of the lining, for which cracks are considered, is characterised with empirical formulas. The pressures of the internal and external surfaces of the lining and the external surface of the consolidation grouting region in each period are calculated. The maximum pressure difference between the lining region and the grouted region for each period are obtained. The effect of emptying speed on the seepage field in the emptying period is also discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
31. Design of erosion protection at diversion tunnel outlets with concrete prisms.
- Author
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Emami, Soleyman and Schleiss, Anton J.
- Subjects
EROSION ,DIVERSION structures (Hydraulic engineering) ,TUNNELS ,PRISMS ,CONCRETE ,HYDRAULIC structures - Abstract
Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2006
- Full Text
- View/download PDF
32. Today and Future Possibilities of Industrial Applications of Drag Reduction
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Pollert, J. and Gampert, Bernhard, editor
- Published
- 1985
- Full Text
- View/download PDF
33. A new model for economic optimization of water diversion system during dam construction using PSO algorithm
- Author
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Sedighizadeh, S., Mansoori, A., Pirestani, M. R., and Davoud Sedighizadeh
- Subjects
Optimization ,Diversion Tunnel ,PSO Algorithm - Abstract
The usual method of river flow diversion involves construction of tunnels and cofferdams. Given the fact that the cost of diversion works could be as high as 10-20% of the total dam construction cost, due attention should be paid to optimum design of the diversion works. The cost of diversion works depends, on factors, such as: the tunnel dimensions and the intended tunneling support measures during and after excavation; quality and characterizes of the rock through which the tunnel should be excavated; the dimensions of the upstream (and downstream) cofferdams; and the magnitude of river flood the system is designed to divert. In this paper by use of the cost of unit prices for tunnel excavation, tunnel lining, tunnel support (rock bolt + shotcrete) and cofferdam fill the cost function was determined. The function is then minimized by the aid of PSO Algorithm (particle swarm optimization). It is found that the optimum diameter and the total diversion cost are directly related to the river flood discharge (Q). It has also shown that in addition to optimum diameter design discharge (Q), river length, tunnel length, is mainly a function of the ratios (not the absolute values) of the unit prices and does not depend on the overall price levels in the respective country. The results of optimization use in some of the case study lead us to significant changes in the cost., {"references":["Iranian Committee On Large Dams, IRCOLD 2005, ","United States Department of Interior, Bureau of Reclamation, (USBR),\nDesign of Small Dams, 3rd Edition, US Government Printing Office,\nWashington DC, USA, 1987.","J. B., Cooke, \"Progress in Rock fill Dams\", J. of Geotechnical\nDivision, ASCE, 110(10), Paper 19206, 1984, pp. 1383-1414","Cai, Junmei , Feng, Jingming, Zhang, Ziji , \"Flood Tunnel with Orifices\nto Control Flow Rate\", Proc. of 4th Int. Conf. On Hydro-Science &\nEngineering (ICHE), 2000, Seoul.","J., Abrishami, V., Rajaee, Naser, \"Concrete Dams (Design and\nConstruction), 2005.","H.W, King, \"Handbook of Hydraulics, 3ed, McGrawHill Company, New\nYork, 1939.","United States Geological Survey, USGS 2007, < http://www.usgs.gov>","S, Rao, Singiresu ., \"Engineering optimization (Theory and Practice)\",\nThird Edition, 1996., School of Mechanical Engineering, Purdue\nUniversity , West Lafayette, Indiana, A Wiley- Interscience Publication,\nJohn Wiley & Sons, Inc.","J., Kennedy and R. C. Eberhart, \"Particle swarm optimization\", Proc.\nIEEE Int. Conf. on Neural Networks, 1995, pp. 1942-1948."]}
34. The safety challenge of river diversion during construction of dams
- Author
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Schleiss, Anton
- Subjects
Design ,Cofferdam ,River closure ,Surface protection ,Diversion tunnel ,Risk assessment - Abstract
The appropriate design of a river diversion system during construction of dam is an essential task since dramatic consequences in view of cost and time overrun may be involved. After a short outline of the different methods of river diversion and its main structural elements, the paper focuses on critical issues in relation with the design of diversion tunnels. For a proper hydraulic functioning of a diversion tunnel a flow acceleration stretch at the entrance is essential, to avoid a too early pressurized flow with rapid increase of the water level upstream of the cofferdam which may lead to overtopping and failure of the latter. The technical challenges of river closure are addressed, which is often a critical phase during construction of a dam. The choice of an economical optimal design discharge of tunnel diversion system is outlined taking into account the risk of flooding of the ongoing onstruction works. In order to reduce the risk of failure of the cofferdams and the diversion tunnel in the case the design flood is exceeded, the design of novel protection methods against erosion of the cofferdam after overtopping as well as against scouring at the outlet of diversion tunnels are presented.
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