Optimization Study on Drainage System for Canal of Middle Route Project of SNWT in Expansive Soil Area with High Groundwater Level

2014 ◽  
Vol 580-583 ◽  
pp. 2023-2028
Author(s):  
Hao dong Cui ◽  
Jia Fa zhang ◽  
Guo Sheng zhu ◽  
De Xu Wu ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Water Level ◽  
Groundwater Level ◽  
Water Pressure ◽  
Drainage System ◽  
Expansive Soil ◽  
Control Measures ◽  
Seepage Field ◽  
Finite Element Technology ◽  
North Water ◽  
Soil Area

The seepage field regulation is important for the stability canal liner plate and slope for along the Middle Route of the South-to-North Water Transfer Project, especially for stretches excavated in expensive soil area with groundwater level. In order to analyzing the rationality and efficiency of seepage regulation measures comprehensively, a typical section was modeled, and the seepage field was simulated with the 3D finite element technology. The distribution of seepage field was analyzed and the seepage control measures were compared. The results show that water pressure on the underside of canal pavement would be reduced significantly by the measures, such as the measure of drainage cushion with drainage holes which open just when ground water level is higher than the canal water level, the measure with drainage cushion replaced by the drainage board. The differences among the two kinds of measure were compared. Their application conditions were discussed and proposed.

Numerical Study of Unsaturated Expansive Soil Canal Slope Covered by Geo-Membrane

2015 ◽  
Vol 744-746 ◽  
pp. 551-554
Author(s):  
Wen Qing Wu ◽  
Jiang Hu Chen ◽  
Hong Yu Zhang ◽  
Jun Hua Wu
Keyword(s):  
Water Content ◽  
Water Level ◽  
Soil Water ◽  
Soil Water Content ◽  
Pore Water Pressure ◽  
Numerical Study ◽  
Water Pressure ◽  
Expansive Soil ◽  
Seepage Field ◽  
Unsaturated Expansive Soil

In view of the holes appearing in different areas of geo-membrane when the geo-membrane technology is applied to the unsaturated expansive soil canal slope, the VADOSE/W is used to analyze the pore-water pressure of the internal canal slope by changing the falling water level. The results show that the hole is nearer to the toe of slope, its effect on the whole seepage field is greater. The greater the rate is, the soil water content is greater.

Interaction between water pressure in the basal drainage system and discharge from an Alpine glacier before and during a rainfall-induced subglacial hydrological event

1997 ◽  
Vol 24 ◽  
pp. 288-292 ◽  
Author(s):  
Andrew P. Barrett ◽  
David N. Collins
Keyword(s):  
Water Level ◽  
Water Pressure ◽  
Drainage System ◽  
Water Levels ◽  
Drainage Network ◽  
Alpine Glacier ◽  
Hydraulic Conditions ◽  
Borehole Water ◽  
Progressive Growth ◽  
Resultant Increase

Combined measurements of meltwater discharge from the portal and of water level in a borehole drilled to the bed of Findelengletscher, Switzerland, were obtained during the later part of the 1993 ablation season. A severe storm, lasting from 22 through 24 September, produced at least 130 mm of precipitation over the glacier, largely as rain. The combined hydrological records indicate periods during which the basal drainage system became constricted and water storage in the glacier increased, as well as phases of channel growth. During the storm, water pressure generally increased as water backed up in the drainage network. Abrupt, temporary falls in borehole water level were accompanied by pulses in portal discharge. On 24 September, whilst borehole water level continued to rise, water started to escape under pressure with a resultant increase in discharge. As the drainage network expanded, a large amount of debris was flushed from a wide area of the bed. Progressive growth in channel capacity as discharge increased enabled stored water to drain and borehole water level to fall rapidly. Possible relationships between observed borehole water levels and water pressures in subglacial channels are influenced by hydraulic conditions at the base of the hole, distance between the hole and a channel, and the nature of the substrate.

Interaction between water pressure in the basal drainage system and discharge from an Alpine glacier before and during a rainfall-induced subglacial hydrological event

1997 ◽  
Vol 24 ◽  
pp. 288-292 ◽  
Author(s):  
Andrew P. Barrett ◽  
David N. Collins
Keyword(s):  
Water Level ◽  
Water Pressure ◽  
Drainage System ◽  
Water Levels ◽  
Drainage Network ◽  
Alpine Glacier ◽  
Hydraulic Conditions ◽  
Borehole Water ◽  
Progressive Growth ◽  
Resultant Increase

Combined measurements of meltwater discharge from the portal and of water level in a borehole drilled to the bed of Findelengletscher, Switzerland, were obtained during the later part of the 1993 ablation season. A severe storm, lasting from 22 through 24 September, produced at least 130 mm of precipitation over the glacier, largely as rain. The combined hydrological records indicate periods during which the basal drainage system became constricted and water storage in the glacier increased, as well as phases of channel growth. During the storm, water pressure generally increased as water backed up in the drainage network. Abrupt, temporary falls in borehole water level were accompanied by pulses in portal discharge. On 24 September, whilst borehole water level continued to rise, water started to escape under pressure with a resultant increase in discharge. As the drainage network expanded, a large amount of debris was flushed from a wide area of the bed. Progressive growth in channel capacity as discharge increased enabled stored water to drain and borehole water level to fall rapidly. Possible relationships between observed borehole water levels and water pressures in subglacial channels are influenced by hydraulic conditions at the base of the hole, distance between the hole and a channel, and the nature of the substrate.

Waterproofing and Drainage System Design of YUN-GUI Express Railway Cutting Sub-Grade in Expansive Soil Area

2014 ◽  
Vol 602-605 ◽  
pp. 799-805
Author(s):  
Xiao Yang ◽  
Guo Lin Yang
Keyword(s):  
Field Test ◽  
Working Condition ◽  
Drainage System ◽  
Expansive Soil ◽  
Reference Value ◽  
Underground Water ◽  
Railway Construction ◽  
Combined Action ◽  
Soil Area

According to the character and generation mechanism of railway cutting sub-grade diseases, following the needs of YUN-GUI express railway construction, based on the results of laboratory and field test of expansive soil engineering characteristics, developed new waterproof material, designed waterproofing and drainage system of cutting sub-grade, and full-scale dynamic model test was carrying out, a cycle load with 4Hz frequency and 4000 thousand times excitation was imposed on the sub-grade model under three kinds of working condition (dry, raining and underground water rising). The results indicate that: no cracks appeared on the surface of semi-rigid waterproof layer, its durability is good. Waterproofing and drainage system of cutting sub-grade works well under combined action of long term cycle load and complicated environment. Research results possess important engineering reference value.

scholarly journals Experimental Study on the Negative Skin Friction of the Pile Group Induced by Rising and Lowering the Groundwater Level

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yu Zhang ◽  
Li-Pei Zhou ◽  
Ming-Yuan Wang ◽  
Xuanming Ding ◽  
Chenglong Wang
Keyword(s):  
Water Level ◽  
Skin Friction ◽  
Axial Force ◽  
Groundwater Level ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Pile Group ◽  
Negative Skin Friction ◽  
Influence Of Water ◽  
Bearing Characteristic

Negative skin friction (NSF) has been one of the important factors in the design of pile foundation; especially, the influence of water level on the pile negative skin friction should be paid attention. In this paper, a series of model tests were carried out to analyze the bearing characteristic of the pile group influenced by groundwater level. The pile axial force and negative skin friction, settlement, and soil pore pressure were investigated. The results showed that both the water level rising and lowering cycle could increase the axial force of the pile along the upper part of the pile, yet reducing it along the lower part of the pile; both the axial force and the negative skin friction of the pile presented a feature of time effect; the value of negative skin friction was positively correlated with that of the pile head load, and the neutral plane ranged from 0.57 L to 0.64 L as the water level changed; the soil featured settling in layers, and the change of pore water pressure was accordant with the water level changing regulation.

On the Seepage Stability of a Tailing Dam in Wushan Copper Mine

2012 ◽  
Vol 594-597 ◽  
pp. 207-212
Author(s):  
Liang Song ◽  
Zhen Xing Yang ◽  
Hao Wang ◽  
Zi Hao Wang ◽  
Huan Qiang Zhang
Keyword(s):  
Water Level ◽  
Early Stage ◽  
Drainage System ◽  
Scientific Basis ◽  
Local Deformation ◽  
Field Conditions ◽  
Tailing Pond ◽  
Seepage Field ◽  
Copper Mine ◽  
Tailing Dam

The tailing pond of Wushan copper mine is located in a valley among the mountains, with kinds of hidden troubles like the overflow of the saturation line, the swamping and piping of partial section, and some local deformation, which appeared on both the starter dam and the tailing embankment in the early stage. To meet the requirement of production, a new tailing pond named No.2 Tailing Pond was built in the downstream of the original No.1tailing pond. At present, in No.1 dam, the part below 37m water level was totally submerged by the water, then the condition of the seepage field will change with the rising water level. For the safety of production and to provide a scientific basis to the management of the tailing dam, an analysis of seepage stability at four different conditions of two sections was carried out based on the field conditions of the dam. Finally, a comparison between the simulated results and the measured results was made, the results show that the existing drainage system is safe and effective, and the seepage deformation of Wushan tailing dam will not happen.

scholarly journals Piezometric Observations of Water Pressure at the Bed of Swiss Glaciers

1979 ◽  
Vol 23 (89) ◽  
pp. 429-430 ◽  
Author(s):  
H. Röthlisberger ◽  
A. Iken ◽  
U. Spring
Keyword(s):  
Water Supply ◽  
Diurnal Variation ◽  
Water Level ◽  
Water Pressure ◽  
Drainage System ◽  
Extended Period ◽  
Hot Water ◽  
Surface Velocity ◽  
Drainage Pattern ◽  
Large Area

AbstractA technique for drilling deep holes with a hot-water jet has been developed in recent years at our institute (Iken and others, [1977]). The holes have served to investigate the water pressure at the bed of various Swiss glaciers since 1973. Drainage occurred naturally in rare cases when the drill reached the bed, but more often it was necessary to use explosives first, probably because the drill was stopped short of the bottom of the glacier by rock inclusions in the ice. In order to record piezometric water pressure over an extended period of time it was necessary that water was draining fairly continuously into the hole, otherwise the water level dropped eventually to a great depth when the weather turned cold, whereupon the holes closed off. By suddenly shutting off the water supply to a hole and observing the lowering of the water level with time some information on the channel characteristics has been obtained. In many cases there was little change of level, indicating that such a hole gives almost the true pressure head of the subglacial drainage system.Our efforts have so far been concentrated on flat tongues of fair size over 100 m thick, the distance from the uppermost hole to the terminus ranging from about 1 to 4.5 km. The main characteristic of the water pressure is a very large diurnal variation of the order of 100 m and more. The mean pressure generally rises and falls in times of high and low water supply, respectively, but re-adjusts to approximately the original level within a few days. Mean levels are higher early in the melt season than later, and the amplitude of the diurnal variation has a tendency to increase with time, but also shows strong short-term modulations depending on the water supply. From observations on moulins and a hole which had remained connected to the bed from the previous year it seems likely that at the beginning of the melt season the water pressure at the bed may become as large as or larger than the ice pressure.On Gornergletscher a record of water pressures has been obtained during the drainage of Gornersee, an ice-dammed lake at the confluence of the two main branches of the glacier. Levels stayed high day and night in the piezometer holes, which were located off to the side of where the main drainage channel was suspected to pass through. The surface drainage pattern was affected over a large area of the glacier. These two observations indicate that during the drainage of the lake some sort of sheet flow must have occurred. The surface velocity of the glacier roughly doubled during that time, but no lifting-up of the ice was observed within the accuracy of the survey. On one occasion on Glacier de Breney the main channel must have been blocked temporarily between an upper area, where the water level was rising simultaneously in three piezometer holes, and an area further down-glacier, where the holes were not affected.

scholarly journals STUDI GEOTEKNIK PENGARUH MUKA AIR TANAH TERHADAP KESTABILAN LERENG TAMBANG BATUBARA

2020 ◽  
Vol 1 (1) ◽  
pp. 475-488
Author(s):  
Jioni Santo Frans ◽  
Muhammad Hafizh Nurfalaq
Keyword(s):  
Rock Mass ◽  
Slope Stability ◽  
Ground Water ◽  
Water Level ◽  
Pore Water ◽  
Groundwater Level ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Slope Angle ◽  
Ground Water Level

ABSTRAK Dalam keadaan normal, suatu massa batuan memiliki kesetimbangan gaya yang bekerja. Kesetimbangan gaya yang bekerja tersebut bisa terganggu akibat terjadinya perubahan kondisi massa batuan, baik secara alamiah (erosi, patah, peningkatan muka air tanah) maupun aktivitas manusia (pengupasan, pengangkutan, penggalian, penimbunan). Respon dari perubahan tersebut, massa batuan dapat mengalami ketidakstabilan sebagai usaha untuk mencapai kondisi kesetimbangan baru. Hal ini akan memicu gerakan massa batuan akibat lereng yang tidak stabil dan terjadinya longsor. Lereng yang tidak stabil akan berdampak terhadap faktor keselamatan, ekonomi, dan sosial. Air tanah memiliki permasalahan tersendiri dalam pengelolaan tambang. Tekanan air pori (pore water pressure) dari air tanah dapat menimbulkan gaya angkat (uplift force) dan menurunkan kekuatan suatu massa batuan penyusun lereng, yang mana akan mempengaruhi kestabilan suatu lereng. Karakteristik daerah penelitian yang memiliki muka air tanah relatif dekat dengan permukaan, menyebabkan lereng berada dalam kondisi hampir jenuh. Penelitian ini bertujuan untuk melakukan studi pengaruh muka air tanah terhadap kestabilan lereng tambang batubara di daerah penelitian. Metode penelitian yang digunakan meliputi pengumpulan data primer melalui observasi lapangan untuk mengumpulkan data-data teknis terkait dan pengumpulan data sekunder melalui studi literatur. Analisa kestabilan lereng dilakukan untuk mendapatkan rekomendasi dengan nilai Faktor Keamanan minimum 1,30. Hasil penelitian menunjukkan muka air tanah memiliki hubungan berbanding terbalik terhadap nilai Faktor Keamanan. Rekomendasi yang dihasilkan yaitu melakukan dewatering dengan menggunakan drain hole. Target penurunan muka air tanah pada dinding tambang daerah penelitian adalah RL+40 pada area sidewall dan RL+65 pada area highwall. Altenatif lain yang diajukan oleh penulis adalah dengan melandaikan sudut lereng keseluruhan (overall slope angle) pada dinding tambang di daerah penelitian. Dinding tambang daerah penelitian direkomendasikan untuk dilakukan pelandaian dengan sudut lereng keseluruhan berkisar 24°. Kata kunci: kestabilan lereng, muka air tanah, longsor, dewatering, sudut lereng keseluruhan  ABSTRACT Under normal circumstances, a rock mass has an equilibrium of working forces. The equilibrium of these working forces can be disrupted due to changes in rock mass conditions, both naturally (erosion, broken, increased ground water level) and human activities (stripping, loading, excavation, backfill). In response to these changes, rock mass can have instability issue as an effort to reach new equilibrium conditions. This  condition will trigger rock mass movements and slope failure due to unstable slopes. Unstable slopes will affect the safety, economic and social factors. Groundwater has its own problems in mining activities. Pore water pressure from ground water can cause uplift force and decrease the strength of a rock mass forming a slope, which will affect the slope stability. Characteristics of the study area which has groundwater level relatively close to surface, causes the slope to be in nearly saturated condition. This research aims to study the effect of groundwater level on the stability of coal mine slopes in the study area. The research method used includes collecting primary data through field observations to collect related technical data and secondary data collection through literature studies. Slope stability analysis is carried out to obtain recommendations with a minimum Safety Factor value of 1.30. The results showed the ground water level has an inverse relationship to the value of the Safety Factor. The recommendations are dewatering using drain holes. The target of groundwater level reduction in the mine wall of the study area is RL+40 in the sidewall area and RL+65 in the highwall area. Another alternative proposed by the author is by resloping the overall slope angle of the mine wall in the study area. The mining wall of the study area is recommended for alignment with an overall slope angle of around 24 °. Keywords: slope stability, ground water level, landslides, dewatering, overall slope angle

Stability Analysis of Unsaturated Expansive Soil Slope Covered by Geo-Membrane

2015 ◽  
Vol 744-746 ◽  
pp. 597-600
Author(s):  
Hong Yu Zhang ◽  
Jiang Hu Chen ◽  
Wen Qing Wu ◽  
Jun Hua Wu
Keyword(s):  
Stability Analysis ◽  
Water Content ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Expansive Soil ◽  
Construction Process ◽  
Soil Slope ◽  
Seepage Field ◽  
Lower Slope ◽  
Unsaturated Expansive Soil

In view of the holes appearing in different area of geo-membrane when the geo-membrane technology is applied to the unsaturated expansive soil slope, the VADOSE/W is used to analyze the wetting-drying cycles caused by rainfall and evaporation on slopes covered by geo-membrane. The influence on the pore-water pressure and volume water content were discussed just caused by the holes. The results show that the hole is nearer to the toe of slope, its impact on the whole seepage field is greater. In addition, the hole appears on the top of slope that the wetting-drying cycle effect is remarkable. It is ensured that the integrity of the geo-membrane which in the lower slope and take some drainage measures in the construction process.

scholarly journals Piezometric Observations of Water Pressure at the Bed of Swiss Glaciers

1979 ◽  
Vol 23 (89) ◽  
pp. 429-430 ◽  
Author(s):  
H. Röthlisberger ◽  
A. Iken ◽  
U. Spring
Keyword(s):  
Water Supply ◽  
Diurnal Variation ◽  
Water Level ◽  
Water Pressure ◽  
Drainage System ◽  
Extended Period ◽  
Hot Water ◽  
Surface Velocity ◽  
Drainage Pattern ◽  
Large Area

Abstract A technique for drilling deep holes with a hot-water jet has been developed in recent years at our institute (Iken and others, [1977]). The holes have served to investigate the water pressure at the bed of various Swiss glaciers since 1973. Drainage occurred naturally in rare cases when the drill reached the bed, but more often it was necessary to use explosives first, probably because the drill was stopped short of the bottom of the glacier by rock inclusions in the ice. In order to record piezometric water pressure over an extended period of time it was necessary that water was draining fairly continuously into the hole, otherwise the water level dropped eventually to a great depth when the weather turned cold, whereupon the holes closed off. By suddenly shutting off the water supply to a hole and observing the lowering of the water level with time some information on the channel characteristics has been obtained. In many cases there was little change of level, indicating that such a hole gives almost the true pressure head of the subglacial drainage system. Our efforts have so far been concentrated on flat tongues of fair size over 100 m thick, the distance from the uppermost hole to the terminus ranging from about 1 to 4.5 km. The main characteristic of the water pressure is a very large diurnal variation of the order of 100 m and more. The mean pressure generally rises and falls in times of high and low water supply, respectively, but re-adjusts to approximately the original level within a few days. Mean levels are higher early in the melt season than later, and the amplitude of the diurnal variation has a tendency to increase with time, but also shows strong short-term modulations depending on the water supply. From observations on moulins and a hole which had remained connected to the bed from the previous year it seems likely that at the beginning of the melt season the water pressure at the bed may become as large as or larger than the ice pressure. On Gornergletscher a record of water pressures has been obtained during the drainage of Gornersee, an ice-dammed lake at the confluence of the two main branches of the glacier. Levels stayed high day and night in the piezometer holes, which were located off to the side of where the main drainage channel was suspected to pass through. The surface drainage pattern was affected over a large area of the glacier. These two observations indicate that during the drainage of the lake some sort of sheet flow must have occurred. The surface velocity of the glacier roughly doubled during that time, but no lifting-up of the ice was observed within the accuracy of the survey. On one occasion on Glacier de Breney the main channel must have been blocked temporarily between an upper area, where the water level was rising simultaneously in three piezometer holes, and an area further down-glacier, where the holes were not affected.

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