scholarly journals Discussion on the Waterproof and Drainage System of the Coastal Tunnel and Analysis of Water Pressure Law outside Lining: A Case Study of the Gongbei Tunnel

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Jinpeng Zhao ◽  
Zhongsheng Tan ◽  
Zhenliang Zhou
Keyword(s):  
Water Pressure ◽  
Water Discharge ◽  
Drainage System ◽  
Free Water ◽  
Water Head ◽  
Free Drainage ◽  
The Stability ◽  
The Relationship ◽  
System Designs

With the orderly promotion of the infrastructure construction in China, the number of coastal tunnels is increasing, but the coastal environment is accompanied by a large amount of groundwater and the designs of the waterproof and drainage system of coastal tunnels have always been a hot topic in the industry. If the waterproof and drainage system designs of the coastal tunnels are improper, the tunnel structure will easily be damaged and the stability and service life of the whole project will be affected. Based on the Gongbei tunnel project of the Hong Kong-Zhuhai-Macao Bridge, this paper discusses the designs of the waterproof and drainage system, and the waterproof detail structures of the Gongbei tunnel. Indoor similarity tests were carried out to study the law of the free water discharge of the tunnel under variable water heads, the relationship between the water pressure outside the lining and the water discharge, the relationship between the water pressure outside the pipe roof and the water discharge, and the distribution of water pressure around the tunnel. The reliability of the indoor similarity test was verified by the field test. The results show that the whole waterproof system should be adopted in the Gongbei tunnel, that is, grouting ring + pipe roof freezing ring + initial lining + waterproof board + tertiary lining. In a certain range, the greater the water head, the greater the free water discharge of the tunnel. When the water head is large, the free drainage tends to a fixed value. When the tunnel is completely plugged, the water pressure outside the tunnel is distributed from the hydrostatic pressure. When the tunnel adopts drainage measures, the water pressure outside the lining will be reduced to a certain extent even the water discharge is very small. The above research can provide a reference for the design of the waterproof and drainage system similar to the coastal tunnel in the future.

scholarly journals Erosion rates and sediment yields of glaciers

1996 ◽  
Vol 22 ◽  
pp. 48-52 ◽  
Author(s):  
Jim Bogen
Keyword(s):  
Water Pressure ◽  
Water Discharge ◽  
Drainage System ◽  
Sediment Concentration ◽  
Pressure Drops ◽  
Sediment Yields ◽  
Erosion Rates ◽  
Slow Moving ◽  
The Relationship ◽  
Subglacial Drainage

Sediment yields and glacial erosion rates are evaluated for four Norwegian glaciers during the years 1989-93. Annual erosion rates were determined from measurements of sediment load and water discharge in glacial meltwater rivers. The mean sediment yield and the corresponding erosion rate of the valley glaciers Engabreen and Nigardsbreen were found to be 456 t km−2year−1(0.168 mm year−1) and 210 t km−2year−1(0.078 mm year−1), respectively. A small and slow-moving cirque glacier Øvre Beiarbre yielded a rate of 482 t km−2year−1(0.178 mm year−1), and the sub-polar Svalbard glacier Brøggerbreen yielded 613 t km−2year−1(0.226 mm year−1). The erosion rates are low compared to glaciers elsewhere. There are also considerable variations in sediment yields at each glacier from year to year. However, different factors are found to control the variability on each individual glacier. Analysis of the relationship between water discharge and sediment concentration in meltwater rivers suggests that changes in subglacial drainage systems cause variations in sediment availability and the way sediments are melted out from the ice. When water pressure drops, the drainage system in fast-moving, thick valley glaciers deforms at a more rapid rate than in thin, slow-moving ones. New volumes of debris-laden ice are thus more readily available for melting when water pressure next increases. Beneath the thin, slow-moving Øvre Beiarbre, single years with high transport rates and evacuation of sediment are followed by periods of low availability lasting for 2 years or longer. It is suggested that this pattern results from exhaustion of sediment in a stable drainage system, with more sediment becoming available when the position of the subglacial drainage system is changed.

scholarly journals Erosion rates and sediment yields of glaciers

1996 ◽  
Vol 22 ◽  
pp. 48-52 ◽  
Author(s):  
Jim Bogen
Keyword(s):  
Water Pressure ◽  
Water Discharge ◽  
Drainage System ◽  
Sediment Concentration ◽  
Pressure Drops ◽  
Sediment Yields ◽  
Erosion Rates ◽  
Slow Moving ◽  
The Relationship ◽  
Subglacial Drainage

Sediment yields and glacial erosion rates are evaluated for four Norwegian glaciers during the years 1989-93. Annual erosion rates were determined from measurements of sediment load and water discharge in glacial meltwater rivers. The mean sediment yield and the corresponding erosion rate of the valley glaciers Engabreen and Nigardsbreen were found to be 456 t km−2 year−1 (0.168 mm year−1) and 210 t km−2 year−1 (0.078 mm year−1), respectively. A small and slow-moving cirque glacier Øvre Beiarbre yielded a rate of 482 t km−2 year−1 (0.178 mm year−1), and the sub-polar Svalbard glacier Brøggerbreen yielded 613 t km−2 year−1 (0.226 mm year−1). The erosion rates are low compared to glaciers elsewhere. There are also considerable variations in sediment yields at each glacier from year to year. However, different factors are found to control the variability on each individual glacier. Analysis of the relationship between water discharge and sediment concentration in meltwater rivers suggests that changes in subglacial drainage systems cause variations in sediment availability and the way sediments are melted out from the ice. When water pressure drops, the drainage system in fast-moving, thick valley glaciers deforms at a more rapid rate than in thin, slow-moving ones. New volumes of debris-laden ice are thus more readily available for melting when water pressure next increases. Beneath the thin, slow-moving Øvre Beiarbre, single years with high transport rates and evacuation of sediment are followed by periods of low availability lasting for 2 years or longer. It is suggested that this pattern results from exhaustion of sediment in a stable drainage system, with more sediment becoming available when the position of the subglacial drainage system is changed.

scholarly journals Water Pressure in Intra- and Subglacial Channels

1972 ◽  
Vol 11 (62) ◽  
pp. 177-203 ◽  
Author(s):  
Hans Röthlisberger
Keyword(s):  
Sediment Load ◽  
Water Pressure ◽  
Drainage System ◽  
Water Layer ◽  
Frictional Heat ◽  
Overburden Pressure ◽  
Bed Topography ◽  
Water Head ◽  
Local Topography ◽  
Dependent Flow

AbstractWater flowing in tubular channels inside a glacier produces frictional heat, which causes melting of the ice walls. However the channels also have a tendency to close under the overburden pressure. Using the equilibrium equation that at every cross-section as much ice is melted as flows in, differential equations are given for steady flow in horizontal, inclined and vertical channels at variable depth and for variable discharge, ice properties and channel roughness. It is shown that the pressure decreases with increasing discharge, which proves that water must flow in main arteries. The same argument is used to show that certain glacier lakes above long flat valley glaciers must form in times of low discharge and empty when the discharge is high, i.e. when the water head in the subglacial drainage system drops below the lake level. Under the conditions of the model an ice mass of uniform thickness does not float, i.e. there is no water layer at the bottom, when the bed is inclined in the down-hill direction, but it can float on a horizontal bed if the exponentnof the law for the ice creep is small. It is further shown that basal streams (bottom conduits) and lateral streams at the hydraulic grade line (gradient conduits) can coexist. Time-dependent flow, local topography, ice motion, and sediment load are not accounted for in the theory, although they may strongly influence the actual course of the water. Computations have been carried out for the Gornergletscher where the bed topography is known and where some data are available on subglacial water pressure.

scholarly journals Effect of different parameters of heterogeneous dams on safety factor using the neural network. Case study: Marvan dam

2019 ◽  
Vol 32 (02) ◽  
pp. 126-138
Author(s):  
B. Beiranvand ◽  
A. Mohammadzade ◽  
M. Komasi
Keyword(s):  
Neural Network ◽  
Factor Of Safety ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Drainage System ◽  
Friction Angle ◽  
The Body ◽  
The Neural Network ◽  
The Cost

The drainage system is used to guide the flow of water in the earth dams. Construction of drainage in the dam body to collect and direct the drainage formed in the dam body to keep the slope dry and prevent the increase of pore water pressure in the body. One of the main goals of the designers is to find the minimum factor of safety and, consequently, reduce the cost of construction. In this study, the Marvak dam is modeled with the actual characteristics of the materials in the Geostudio software, and with the change in the dimensions of the drain, the material and the slope of the dam body, the minimum Factor of safety of the dam is obtained. In order to predict the minimum Factor of safety, a two-layer neural network has been used. With the training of the neural network based on the data obtained from heterogeneous dams, a minimum Factor of safety has been extracted for optimization of drainage. Finally, it was determined that the internal friction angle of the body material and the slope of the dam have the greatest effect on the dam factor of safety.

scholarly journals Water Pressure in Intra- and Subglacial Channels

1972 ◽  
Vol 11 (62) ◽  
pp. 177-203 ◽  
Author(s):  
Hans Röthlisberger
Keyword(s):  
Sediment Load ◽  
Water Pressure ◽  
Drainage System ◽  
Water Layer ◽  
Frictional Heat ◽  
Overburden Pressure ◽  
Bed Topography ◽  
Water Head ◽  
Local Topography ◽  
Dependent Flow

AbstractWater flowing in tubular channels inside a glacier produces frictional heat, which causes melting of the ice walls. However the channels also have a tendency to close under the overburden pressure. Using the equilibrium equation that at every cross-section as much ice is melted as flows in, differential equations are given for steady flow in horizontal, inclined and vertical channels at variable depth and for variable discharge, ice properties and channel roughness. It is shown that the pressure decreases with increasing discharge, which proves that water must flow in main arteries. The same argument is used to show that certain glacier lakes above long flat valley glaciers must form in times of low discharge and empty when the discharge is high, i.e. when the water head in the subglacial drainage system drops below the lake level. Under the conditions of the model an ice mass of uniform thickness does not float, i.e. there is no water layer at the bottom, when the bed is inclined in the down-hill direction, but it can float on a horizontal bed if the exponent n of the law for the ice creep is small. It is further shown that basal streams (bottom conduits) and lateral streams at the hydraulic grade line (gradient conduits) can coexist. Time-dependent flow, local topography, ice motion, and sediment load are not accounted for in the theory, although they may strongly influence the actual course of the water. Computations have been carried out for the Gornergletscher where the bed topography is known and where some data are available on subglacial water pressure.

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.

scholarly journals The relationship between subglacial water pressure and velocity of Findelengletscher, Switzerland, during its advance and retreat

1997 ◽  
Vol 43 (144) ◽  
pp. 328-338 ◽  
Author(s):  
Almut Iken ◽  
Martin Truffe
Keyword(s):  
Water Pressure ◽  
Pressure Fluctuations ◽  
Drainage System ◽  
Surface Strain ◽  
Aerial Photographs ◽  
Surface Velocity ◽  
Surface Geometry ◽  
Sliding Speed ◽  
Pressure Surface ◽  
The Relationship

AbstractFindelengletscher, Switzerland, advanced about 250 m between 1979 and 1985, and retreated thereafter. Subglacial water pressure, surface velocity and surface strain rate were determined at several sites. The measurements were made early in the melt seasons of 1980, 1982, 1985 and 1994 and in the autumn of 1983 and the winter of 1984. Changes of surface geometry were assessed from aerial photographs.The estimated basal shear stress changed little between 1982 and 1994. Nevertheless, large changes in the relationship of subglacial water pressure and surface velocity were observed, which cannot be reconciled with the most commonly used sliding law unless it is modified substantially. Consideration of possible reasons indícales that a change in the subglacial drainage system occurred, probably involving a change in the degree of cavity interconnection. Isolated cavities damp the variations in sliding velocity that normally result from changes in water pressure, because the pressure in isolated cavities decreases as the sliding speed increases. In contrast, by transmitting water-pressure fluctuations to a larger area of the bed, interconnected cavities amplify the effect of water-pressure fluctuations on sliding speed. Thus, we suggest that an observed decrease in velocity (for a given water pressure) between 1982 and 1994 was a consequence of a decrease in the interconnectedness of the subglacial cavity system.

Land Price Modelling with Radial Basis Function (Case Study: Utan Kayu Selatan Village, East Jakarta)

2021 ◽  
Vol 5 (1) ◽  
pp. 473-479
Author(s):  
Sawitri Subiyanto ◽  
Hana Sugiastu Firdaus ◽  
Nahar Dito Utama Giardi
Keyword(s):  
Radial Basis Function ◽  
Basis Function ◽  
Property Market ◽  
Market Prices ◽  
Land Prices ◽  
Public Facilities ◽  
Radial Basis ◽  
The Stability ◽  
The Relationship

The price of land is an important matter that needs to be assessed by stakeholders. The study of land prices has an important role in seeing the stability of the property market. Several factors affect the property business such as accessibility, public facilities and social facilities. Utan Kayu Selatan is the largest village in Matraman Sub-District with an area of ​​1,12 kilometers. The potential of the property business is very tempting for investors to property developers. One of the economic sector developments is Utan Kayu Raya Road, which can increase land prices in the surrounding area. The factors that influence land prices can be analyzed through several approaches such as regression, mass appraisal and other. In this study, the method used in estimating land prices is the Radial Basis Function (RBF), by looking at the relationship between the distance of plot to roads, public facilities and social facilities. Modeling is carried out based on samples determined on ZNT and NJOP land prices. Furthermore, the calculation of the distance is done by using network analysis. As a result, the RMSE value for the NJOP RBF model and the ZNT RBF model is IDR 1.179.839 and IDR 2.972.345. Meanwhile, the CoV values ​​for both models were 6.2% and 6%. In the comparison of ZNT price predictions with market prices, the highest difference is IDR 13.119.915 and the lowest difference is IDR 537.009. While on the NJOP price prediction, the highest difference is IDR 15.797.583 and the lowest difference is IDR 291.270.

Numerical Simulation of Grout Curtain in a DEWPR Tunnel

2011 ◽  
Vol 250-253 ◽  
pp. 1873-1876
Author(s):  
Jian Xiu Wang ◽  
Bo Feng ◽  
Pei Wang ◽  
Yi Qun Tang ◽  
Ping Yang
Keyword(s):  
Discharge Rate ◽  
Water Pressure ◽  
Unit Length ◽  
Water Discharge ◽  
Drainage System ◽  
Grout Curtain ◽  
Control Factor ◽  
External Water Pressure ◽  
Grouting Reinforcement ◽  
External Water

Grouting is often adopted in a tunnel to resist high external water pressure; the tunnel is defined as External Water Pressure-Resistant Tunnel (EWPR Tunnel). When the grouting reinforcement does not seal the high pressure groundwater completely and the leakage groundwater is drained by drainage system, the tunnel can be called a Drained External Water Pressure -Resistant Tunnel with limited Drainage (DEWPR Tunnel), the grouting reinforcement and waterproof/drainage system of which are great important and should be considered specially. Take the traffic tunnels of Jinping Second Cascade Hydropower Station as an example, a numerical method is adopted to simulate the influence of grouting reinforcement thickness on the distribution of external water pressure. The results indicate that the discharge rate per unit length is 7.82m2/d with single tunnel drainage and 5.28m2/d with double-tunnel drainage, and the external water pressure can be reduced less than 0.6MPa when the thickness of grouting reinforcement is 12m based on the control factor of volume of water discharge.

scholarly journals Instability of flood embankments due to pore-water pressure build-up at the toe: lesson learned from the Adige River case study

2020 ◽  
Vol 57 (12) ◽  
pp. 1844-1853 ◽  
Author(s):  
Alessia Amabile ◽  
Annarita Pozzato ◽  
Alessandro Tarantino
Keyword(s):  
Cross Sections ◽  
Hydraulic Properties ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Critical Role ◽  
Site Investigation ◽  
First Order ◽  
First Order Second Moment ◽  
The Stability

A case study is presented of the Adige River embankment, a segment of which experienced instability of the landside slope due to the development of uplift pressures. Soil profile and hydromechanical properties of the embankment and foundation materials have been assessed via site investigation, laboratory testing, and field monitoring for two cross sections, within and outside the failure segment. The hydromechanical model developed thereof was first validated against its ability to reproduce the probability of failure for the two sections with a first-order, second-moment (FOSM)-based approach. Comparison of water flow regimes between the two sections was then used to highlight the importance of the hydraulic properties of the material on the landside for the development of uplift pressures at the toe of the embankment. The lesson learnt from this case study is that the hydraulic response of the ground on the landside may play a critical role on the stability of flood embankments and its characterization should therefore not be overlooked when planning site investigation.

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