scholarly journals Developent and Application of Hybrid Method to Inhomogeneous Geology for Curtain Grouting -Case Study in Sedimentary Rock with Fold Movement for Nam Ngiep 1 Hydropower Project in Lao PDR-

2021 ◽  
Author(s):  
Yoichi Yoshizu ◽  
Kazuo Nakamura ◽  
Tatsuya Kawata ◽  
Takahiro Fujii ◽  
Shoji Tsutsui
Keyword(s):  
Conventional Method ◽  
Sedimentary Rock ◽  
Water Pressure ◽  
Lao Pdr ◽  
Hydropower Project ◽  
Dam Foundation ◽  
Mix Proportion ◽  
Pressure Tests ◽  
Curtain Grouting ◽  
The Individual

Abstract Curtain grouting for dam foundation treatment is one of the most crucial work items in dam construction to secure the impermeability of the foundation rock. Some decades ago, the Grouting Intensity Number (GIN) Method developed in Europe has been frequently applied to relatively simple geotechnical structures. On the other hand, the Conventional Method, which requires phased mix proportion and water pressure tests through a sequence of the works, is as yet reliable for inhomogeneous geology. This paper presents the development of a modified curtain grouting method and its application to the Nam Ngiep 1 Hydropower Project in Lao PDR, which has an inhomogeneous geology of sedimentary rock with weak layers affected by fold movement. The method has been dubbed as “hybrid” because it garners both the economical superiority of the GIN Method in that it enables the use of a single mix proportion, and the technical superiority of the Conventional Method in that the individual design pressure in each stage is based on water pressure tests.

scholarly journals Experimental Study on Hydraulic Fracturing of High Asphalt Concrete Core Rock-Fill Dam

2019 ◽  
Vol 9 (11) ◽  
pp. 2285 ◽  
Author(s):  
Zhengxing Wang ◽  
Jutao Hao ◽  
Jian Yang ◽  
Yan Cao ◽  
Xiulin Li ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
Asphalt Concrete ◽  
Water Pressure ◽  
Concrete Core ◽  
Mix Proportion ◽  
Local Shear ◽  
Test Result ◽  
Rule Out ◽  
Shear Dilatancy

In this paper, we experiment on the hydraulic fracturing of asphalt concrete with a voids content higher than 3%, which has arisen from the possible local shear dilatancy of Quxue asphalt’s core wall of concrete core dam, the highest one of the sort constructed in the world. The model test has shown that under the sole water pressure 0.13 MPa—relevant to the pressure where the dilatancy could appear at core wall of Quxue dam—the asphalt concrete with a voids content of 3.5% underwent hydraulic fracturing. Furthermore, the asphalt concrete with a voids content of 3.0% was tested for nearly 500 h and no sign of hydraulic fracturing was found, which again confirmed the threshold requirement for a 3% voids content to the impervious asphalt concrete to the hydraulic fracture concern. According to the analysis of the test result, the theory of fracture mechanics could be applied to the hydraulic fracture of asphalt concrete with a voids content between 3.4~4.0%, which behaved during hydraulic fracturing like a quasi-brittle material, similar to concrete. Because the hydraulic fracturing could occur in the shear dilatant asphalt concrete, a proper mix proportion of asphalt concrete to a project with adverse stress state should be carefully designed to rule out the possibility of shear dilatancy.

Optimum Conditions for the Operation of Airline Aircraft

1953 ◽  
Vol 57 (512) ◽  
pp. 524-527 ◽  
Author(s):  
Alan H. Stratford
Keyword(s):  
Conventional Method ◽  
Direct Costs ◽  
Profit Margin ◽  
Optimum Conditions ◽  
Transport Aircraft ◽  
The Subject ◽  
Aircraft Type ◽  
The Individual ◽  
Insight Into

The Conventional method of assessing the direct costs or the aircraft type costs on a passenger mile or ton mile basis does not necessarily give a sufficient indication of the economic merit of a particular type of transport aircraft. It can be misleading when comparing aircraft of widely different design, and it does not indicate the best routes for effective airline exploitation.The profit margin in relation to the fundamental cost or investment unit of the individual airline must be the ultimate yardstick of transport aircraft selection and this is here analysed with a view to providing further insight into the optimum conditions for potential profits. This study of the subject draws attention to the primary factors involved and suggests a criterion which can be simplified into a form valid for most airline economies.

Hydraulic Conductivity and Scale Effects Investigation in Basalt in the Dam Area of Xiluodu Hydroelectric Station, Jinshajiang River, China

2013 ◽  
Vol 405-408 ◽  
pp. 2123-2129
Author(s):  
Yuan Yao Li ◽  
Rong Lin Sun ◽  
Ren Quan Chen
Keyword(s):  
Hydraulic Conductivity ◽  
Scale Effects ◽  
Fractured Rock ◽  
Water Pressure ◽  
Hydroelectric Station ◽  
Tracer Test ◽  
Test Results ◽  
Hydraulic Test ◽  
Water Seepage ◽  
Pressure Tests

Hydraulic conductivity (K) and scale effects in basalt in the dam area of Xiluodu hydroelectric station were investigated by three kinds of field hydraulic tests with different test scale, 2608 water pressure tests in single borehole, 54 water seepage tests in adit and groundwater tracer test. Statistical results show the high heterogeneity of fractured rock and K difference between two neighboring test intervals are often more than two orders of magnitude. However, there is a strong decreasing trend of hydraulic conductivity with the increase of vertical depth. Moreover, these three kinds of hydraulic test results demonstrate that hydraulic conductivity increases with the increase of test scale in heterogeneous basalt and the heterogeneous degree of K decreases with the increase of test scale. K from water seepage test in adit, with the test scale of 1-2 m, is dispersed from 0.00024 m/d to 3.46 m/d. K from water pressure test in single borehole, with the test scale of 4-7 m, is 0.0002-1.04 m/d. K from groundwater tracer test, with the test scale of 70-145 m, is concentrated between 0.46 m/d and 2.1 m/d. High heterogeneity of fractured rock and multi-level of fractures are thought as the major reason resulted in scale effects of hydraulic conductivity.

Three-Dimensional Seepage Analysis and Seepage Control System Optimization of a Hydropower Project

2012 ◽  
Vol 468-471 ◽  
pp. 2433-2436
Author(s):  
Wen Ting Zhan ◽  
Qing Xu
Keyword(s):  
Control System ◽  
Three Dimensional ◽  
System Optimization ◽  
Field Analysis ◽  
Hydropower Project ◽  
Seepage Field ◽  
Seepage Analysis ◽  
Dam Foundation ◽  
Seepage Control ◽  
Water Head

The study is conducted for the 3-D seepage field analysis and the seepage control measurements optimization of a hydropower project, which is located in Sichuan Province, China. The seepage control measurements are introduced in this paper. An equivalent method is adopted to simulate drainage holes and the approach of determining equivalent permeability coefficient is presented. The 3-D seepage field with seepage control system is analyzed comprehensively by the water head contours, uplift on the dam foundation, and so on. The necessities of setting the grouting curtain and the drainage holes are discussed respectively. Further the optimal design of the grouting curting and drainage holes of the dam foundation is studied. The results show that special attention should be paid to ensure the well-operation of the seepage control system and the optimization of decreasing the depth of the drainage curtains and grouting curtains properly can be considered.

Seepage Field Study of Xiaowan Hydropower Project

2011 ◽  
Vol 243-249 ◽  
pp. 4501-4505
Author(s):  
Yong Xiang Wang ◽  
Qing Xu ◽  
Ji He ◽  
Sheng Hong Chen
Keyword(s):  
Control System ◽  
Three Dimensional ◽  
Arch Dam ◽  
Hydropower Project ◽  
The Finite Element Method ◽  
Seepage Field ◽  
Dam Foundation ◽  
Initial Flow ◽  
Seepage Control ◽  
Geological Conditions

The Xiaowan Hydropower Project is located in the middle and lower reaches of the Lancang River in Yunnan Province, China. The arch dam of this project, with a height of 294.5m, is by far the highest dam of its type that has been completed in the world. The great water potential makes it necessary to assess the seepage behavior in the dam-foundation system. Due to the complexity of geological conditions and seepage control system, the research is full of challenges. In this paper, the finite element method (FEM) is adopted to simulate the three-dimensional seepage field. The initial flow method and the boundary pre-adjustment method are combined to obtain the seepage free surface and overflow surface under complicated boundary conditions. The hydraulic potential contours, seepage gradient, drainage discharges, and so on, are all analysed and the results show that the seepage control system is reasonable and effective. Furthermore, the results of the seepage field can provide suitable seepage load in the stress-strain and stability analysis for the dam-foundation system of Xianwan. At present, the project is in good operation.

scholarly journals Experimental Investigation on Mechanical Characteristics of Waterproof System for Near-Sea Tunnel: A Case Study of the Gongbei Tunnel

Symmetry ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1524
Author(s):  
Zhenliang Zhou ◽  
Zhongsheng Tan ◽  
Qiang Liu ◽  
Jinpeng Zhao ◽  
Zikai Dong
Keyword(s):  
Mechanical Characteristics ◽  
Water Pressure ◽  
Scale Model ◽  
Construction Process ◽  
Applied Water ◽  
Curtain Grouting ◽  
Free Drainage ◽  
Movement Joint ◽  
Selection Of

The water around thenear-sea tunnels is supplied infinitely, and mechanical characteristics of the lining and movement joint are inevitably affected by waterproof methods. The research on the mechanical characteristics of the waterproof system is immature. As a case study of the Gongbei tunnel, a scale model was established in this study, and the stratum, pipe curtain, grouting circle, lining, waterproof board, and movement joint were simulated based on the similarity theories. By changing the externally applied water pressure and drainage discharge, the variation and distribution of the water pressure and strain on the lining with the fully wrapped waterproof (FWW) method, the lining with the partially wrapped waterproof (PWW) method, and the movement joint were investigated. Furthermore, several suggestions on the selection of the waterproof method were presented. The results indicate that the PWW method can reduce the water pressure and strain on the lining under the drained state. Under the state of free drainage, the strain on the lining with the PWW method may get a discount of about 30%. More attention could be paid to the waterproof of the movement joints in the construction process, especially the invert. The research results may offer some valuable insights into the waterproof design of similar near-sea tunnels.

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