scholarly journals Investigation and Analysis on Crystallization of Tunnel Drainage Pipes in Chongqing

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Xuefu Zhang ◽  
Yuanfu Zhou ◽  
Bin Zhang ◽  
Yuanjiang Zhou ◽  
Shiyang Liu
Keyword(s):  
Groundwater Level ◽  
Laboratory Tests ◽  
Support Structure ◽  
Sem Images ◽  
Tunnel Support ◽  
Site Investigations ◽  
Inner Surface ◽  
Drainage Pipe ◽  
Under Construction

A lot of crystallizations exist on the inner wall of tunnel drainage pipes in Chongqing. Tunnel support structure often bears larger load than usual because the tunnel drainage pipes are blocked easily by the crystals and the groundwater level would rise. In order to investigate what the crystals are, site investigations and laboratory tests of crystals and groundwater were completed. Some valuable results have been obtained. Firstly, the crystallizations are usually discovered in drainage pipe exits of tunnels which are under construction in Chongqing. Furthermore, the results of XRD have confirmed that the crystals are calcite. And calcite morphology could be found in most SEM images. But there are other morphologies in these images other than calcite because calcite is often influenced by some factors, such as important ions in groundwater, pH of groundwater, kinetics effect, and so on. Finally, some steps and solutions to solve blocking of tunnel drainage pipes caused by crystallization are suggested. One of the best solutions is that some special materials which could prevent crystals from being attached to pipes are coated on the inner surface of drainage pipes. The results could contribute to understand the crystallization phenomenon profoundly and help solve the similar situations of tunnel drainage pipe blocking.

scholarly journals SHEAR STRENGTH OF SOILS FROM THE DOBKOVICKY LANDSLIDE IN THE CENTRAL BOHEMIAN UPLANDS DETERMINATED BY LABORATORY TESTS

2017 ◽  
Vol 10 ◽  
pp. 48-51 ◽  
Author(s):  
Jakub Roháč ◽  
Petr Kycl ◽  
Jan Boháč ◽  
David Mašín
Keyword(s):  
Shear Strength ◽  
Laboratory Tests ◽  
Soil Shear Strength ◽  
Under Construction ◽  
Heavy Rains

The aim of this paper is to evaluate soil shear strength from the Dobkovicky landslide. The landslide was activated on June 6, 2013 after heavy rains and the D8 motorway, which was under construction at the time, was damaged. The laboratory tests were carried out on two types of soils, clay and tuff, both from the surface of the rupture. Critical and residual friction angles were evaluated on both types of soils.

scholarly journals Effect of Polyvinyl Acetate Stabilization on the Swelling-Shrinkage Properties of Expansive Soil

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Jin Liu ◽  
Yong Wang ◽  
Yi Lu ◽  
Qiao Feng ◽  
Faming Zhang ◽  
...  
Keyword(s):  
Laboratory Tests ◽  
Polyvinyl Acetate ◽  
Expansive Soil ◽  
Aggregate Size ◽  
Soil Improvement ◽  
Linear Shrinkage ◽  
Test Results ◽  
Pore Filling ◽  
Sem Images ◽  
Particle Encapsulation

Polyvinyl acetate constitutes a class of polymers that can entirely dissolve in water to form a solution. In this study, polyvinyl acetate as a nontraditional chemical stabilizer was used in soil improvement. Laboratory tests were carried out to evaluate the effect of polyvinyl acetate on swelling-shrinkage properties of expansive soil. A series of shrink/swell tests were performed with adding polyvinyl acetate as amendment at a concentration 3 g/cm3 to four aggregate sizes in the range of 0–0.5 mm, 0.5–1 mm, 1-2 mm, and 2–5 mm and five concentrations 1.5 g/cm3, 3 g/cm3, 4.5 g/cm3, 6 g/cm3, and 9 g/cm3 to soils with aggregate size in the range of 0.5–1 mm for comparison of results with those of untreated soils. The results show that all the linear swelling ratio (LSWR) and linear shrinkage ratio (LSHR) values of the treated specimens decrease. SEM images and the test results indicate the achieved reduction in volume change of the soil tested using soil pore filling and particle encapsulation.

scholarly journals Geotechnical Challenges of Tehran Metro Line 7 (South Northern Route)

2018 ◽  
Vol 4 (5) ◽  
pp. 1117
Author(s):  
Farzad Sadjadi ◽  
Ahad Bagherzadeh Khalkhali
Keyword(s):  
Groundwater Level ◽  
Urban Areas ◽  
Laboratory Tests ◽  
Alluvial Soil ◽  
Field Tests ◽  
Geological Hazards ◽  
Human Presence ◽  
Level Of Difficulty ◽  
The Right

Tunneling in urban areas, has raised the level of difficulty and challenge in respecting the constraints deriving from human presence and, therefore, the necessity for the study of geological and geotechnical properties and parameter, classification of the soils according to their engineering behavior, choosing the right TBM, determine groundwater level and determining possible geological hazards. In this paper some geological and geotechnical study took place along the tunnel route. This investigation is done by the result of 73 machinery borehole and 32 manual borehole that took place in the process of studying the tunnel route and continued by the result of field tests and laboratory tests and according to the result, the geological zone classified in 6 zone in tunnel route; due to the result of Cerchar abrasivity test and since Alluvial soil is the main soil in most of the tunneling route, the excavation soil classified as highly abrasive. In some part of tunneling there is a risk of clogging due to the high amount of clay. Based on the results of Lofran tests the permeability of most of the classified soils in route of the tunnel was obtained less that 10E-7 m/s.

Primary haemostasis and its assessment by laboratory tests

2006 ◽  
Vol 26 (01) ◽  
pp. 42-47
Author(s):  
A. J. Reininger
Keyword(s):  
Blood Loss ◽  
Vessel Wall ◽  
Laboratory Tests ◽  
Reliable Data ◽  
Blood Vessel Wall ◽  
Vessel Injury ◽  
Inner Surface ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Three Phases

SummaryPlatelets constantly patrol the inner surface of blood vessels searching leaks to be sealed, in order to prevent blood loss. When they detect a vessel injury their action can be divided into three phases. Adhesion: The platelets adhere to the injured blood vessel wall via their receptors glycoprotein (GP) Ib and integrin α2bβ3 (GPIIb/IIIa) mediated by the ligands von Willebrand factor (VWF), fibrinogen and others. Aggregation: Platelets stick to each other through fibrinogen bridging integrin α2bβ3 (GPIIb/IIIa) on adjacent platelets. Secretion: During activation the content of platelet granules is released by exocytosis, thus augmenting and propagating formation of a haemostatic plug or thrombus.Laboratory tests mimic one or several aspects of these three phases to obtain reliable data on a patients platelet function. In this overview assays, test principles, and pitfalls are presented.

scholarly journals Locating the probable ignition source in fire expertise

2020 ◽  
Vol 305 ◽  
pp. 00042
Author(s):  
Gheorghe Daniel Florea ◽  
Nicolae Ioan Vlasin
Keyword(s):  
Laboratory Tests ◽  
Research Team ◽  
Simulation Software ◽  
Ignition Source ◽  
Fire Simulation ◽  
Dynamic Effects ◽  
Radiation Chemical ◽  
Geometry Modeling ◽  
Site Investigations ◽  
In Fire

An important aspect in elucidating the causes of fire events occurence, is the identification of the initial outbreak following on-site investigations. Based on the information resulting from the event footprint (observed thermal and dynamic effects) in correlation with the results obtained in the laboratory tests on the collected samples, as well as the possible generating scenarios of the event, the most probable sources of ignition can be identified. The research team must thoroughly analyze all elements of thermal, mechanical, electrical, radiation, chemical, etc. which may have been present or incidents in the initial outbreak. The computerized fire simulation software will also be used to verify possible scenarios with geometry modeling, combustible / flammable properties of the real case elements, as well as the location of the ignition source, following that the dynamics and propagation directions of simulated fire to be consistent with the case under consideration.

Influence of Variation of Groundwater Level on Deformation of Subgrade Based on Hydromechanical Coupling

2012 ◽  
Vol 457-458 ◽  
pp. 30-33
Author(s):  
Meng Ling Hu ◽  
Hai Lin Yao ◽  
Jie Liu ◽  
Zheng Lu
Keyword(s):  
Water Content ◽  
Water Level ◽  
Groundwater Level ◽  
Laboratory Tests ◽  
Resilient Modulus ◽  
Great Influence ◽  
Coupling Mechanism ◽  
Hydromechanical Coupling ◽  
Subgrade Soil ◽  
The Relationship

Deformation of subgrade caused by variation of groundwater level is a problem of hydromechanical coupling. The coupling mechanism of seepage and deformation of subgrade was analyzed, and a model of hydromechanical coupling was then established. The resilient modulus of the model is related to the water content and compactness of subgrade soil. The relationship between them was obtained based on laboratory tests, and was employed to research the influence of rise of groundwater level on resilient modulus and deformation of subgrade. The results showed that the rise of water level had great influence on resilient modulus of subgrade, and the deformation of subgrade can’t be neglected.

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