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Studying the stress-suction coupling in soils using an oedometer equipped with a high capacity tensiometer

Frontiers of Structural and Civil Engineering 2011年第2期5卷 160-170页

作者： Trung Tinh LE Yu-Jun CUI Juan Jorge MUÑOZ Pierre DELAGE Anh Minh TANG Xiang-Ling LI Ecole des ponts ParisTech Navier/CERMES6-8av.B.PascalCitéDescartesChamps-sur-Marne77455 Marne-la-Vallée cedex 2France The China Three Gorges University Yichang 443002China EURIDICE Group c/o SCK./CENBoeretang 2002400 MolBelgium

In the context of research into deep nuclear waste disposal,various works have concerned the hydromechanical behavior of Boom clay,a stiff plastic clay extracted in the SCK-CEN Underground Research Laboratory near the Mol City(Belgium),at a depth of 223 *** to some amount of smectite minerals in the clay fraction,Boom clay exhibits swelling properties when hydrated under low *** investigate some aspects of the hydromechanical behavior of Boom clay,oedometer compression tests were carried out on samples of Boom clay close to saturation and submitted to an initial *** oedometer compression,the changes in suction with increased vertical stress are monitored by means of a high capacity tensiometer installed at the bottom of the *** aspects related to hydromechanical couplings are examined through the investigation of the changes in suction during oedometer compression,a somewhat delicate and poorly documented experimental approach.A comparison is also made with a completely different soil sample under suction,i.e.a statically compacted unsaturated low plasticity *** technical difficulties typical of this new experimental approach are first described in detail so as to optimize the interpretation of the data *** experiment allows the determination of the point at which suction is changed to positive pressure during *** this point,the ratio between the vertical stress and the change in suction are *** this point,the data show that positive pore pressures are dissipated in a common *** suction/stress behavior during unloading is also described and ***,an interpretation in terms of microstructure effects is provided for both *** experimental approach initiated here seems to provide interesting further application to better understand hydromechanical couplings in natural soils in relation with suction increase during stress release.

关键词： Oedometer tensiometer swelling physicochemical and mechanical effects stress/suction coupling soil plasticity

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Field instrumentation for real-time measurement of soil-water characteristic curve

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International Soil and Water Conservation Research 2022年第4期10卷 586-596页

作者： Abdul Halim Hamdany Yuanjie Shen Alfrendo Satyanaga Harianto Rahardjo Tsen-Tieng Daryl Lee Xuefeng Nong School of Civil and Environmental Engineering Nanyang Technological UniversityBlock N1#B1a-01a50 Nanyang AvenueSingapore639798 Department of Civil and Environmental Engineering Nazarbayev UniversityNur-Sultan010000Kazakhstan School of Civil and Environmental Engineering Nanyang Technological UniversityBlock N1#1B-3650 Nanyang AvenueSingapore639798 CUGE Research National Parks Board Singapore1 Cluny RdSingapore259569

Suction measurement has a vital role in unsaturated soil ***,measuring soil suction remains a challenging task due to a number of issues such as the limited range of suction measurement,cavitation,or long equilibrium *** is even more challenging when the suction measurement is to be carried on the ***,the development of a new suction measurement device which is able to measure high suction range for a long duration without tedious maintenance and yet portable enough for site measurement is *** this study,a new sensor which is referred to as NTU Osmotic tensiometer was developed along with the method to correct for decay and *** NTU osmotic tensiometer is based on polymer swelling capacity in order to measure in-situ soil suction in real time for a very long *** requires minimum maintenance as the polymer-based sensor is not affected by the cavitation ***,correction for decay and temperature is of paramount importance and therefore explained in this *** of the NTU osmotic tensiometer was carried out by comparing the field measurement results from the NTU osmotic tensiometer and the small tip *** performance of the NTU osmotic tensiometer was found to be comparable with that of the small tip tensiometer,but the NTU osmotic tensiometer is able to measure more than 100 kPa soil ***,it is possible to obtain the field soil-water characteristic curve by combining the measured in-situ soil suction from the NTU osmotic tensiometer with the measured in-situ water content from the moisture sensor as illustrated in the paper.

关键词： Suction measurement tensiometer Moisture sensor SWCC Field measurement

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Water Flow Path Characterization in Shallow Vadose Zone Using tensiometers

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Journal of Water Resource and Protection 2017年第9期9卷 1082-1096页

作者： Mohammad Hassan Rezaie-Boroon Omar Acosta Rodrigo Chipres Cheryl Cox Frank Diemel Norman Ho Shaonan Li Ricardo Lopez Matthew Luque Mayra Martinez Dennis Palacios James Wright Geosciences and Environment Department California State University Los s Angeles USA

In this project, we will present the findings of a study using tensiometer systems designed to investigate the water flow path pattern in shallow vadose zone. The purpose of this paper is to evaluate water flow path in shallow vadose zone and to calculate the infiltration rate and hydraulic conductivity of a soil using tensiometer. We have measured the subsurface water flow paths in sandy clay loam soil following infiltration experiment using tensiometers. The matric potential and hydraulic conductivity measurements show that subsequent infiltration and water movement in unsaturated (vadose) zone are vertical, but it can have large lateral component under steady condition. This shows that water moves generally from high water content to lower water content region. Average pressure head for the percolation test conduction locations EB and HB was -30 and -80 cm respectively. Hysteresis produces another interesting situation when the soil is drained. We found that the wetter portion of the soil in vadose zone could be at a lower potential (head) than the dryer portions, resulting in lateral driving force for a preferential flow of water from the dryer to the wet soil. The infiltration rate for the 5 cm ponded water was calculated at 5.45 cm/hr. The infiltration rate curve shows that the rate of infiltration decreases with the time. When infiltration first starts, the wetting front is steep and very close to the surface. Similarly, due to the pressure head gradient, large value for infiltration is recorded. Under these conditions, we believe that the gradient in pressure head is responsible for the rapid movement of water into the dry soil. The effect of gravity is less on water during the initial stages of infiltration;however, it is more effective for preferential flow pattern. In the latter infiltration event, the wetting front has moved deeper into the soil. As a result, the pressure head gradient at the surface is much smaller and consequently has little effect. Wh

关键词： tensiometer Water Pollution Contamination Migration Infiltration Vadose Zone

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Future of Treatment of Temporomandibular Joint Dysfunctions in Parkinsonian Patients

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Open Journal of Stomatology 2014年第4期4卷 208-227页

作者： Reda Ahmed Nofal Alaa Abdelqader Altaweel Yasser Ibrahim Seada Assistant Professor Department of Physical Therapy Cairo University Giza Egypt Associate Professor of Oral and Maxillofacial Surgery Faculty of Dentistry Alazher Lecturer of Oral and Maxillofacial Surgery Faculty of Dentistry Alazher University Cairo Egypt

The purpose of the study was designed to clarify the modern trends of physical therapy in treatment of temporomandibular joint dysfunctions in Parkinsonian patients, which in this respect included the degree of pain, the muscles power of both masseter and pterygoid, the range of TMJ motion, the angle of mouth opening and their effects on electromyography study in both sexes. Subjects: Thirty males and females were the same degree of disabilities according to modified Hoehn and Yahr scales (grade 3) of Parkinsonian patients, and their age ranged from 50 - 77 years old and their weight ranged from 60 - 88 kg. They were randomly divided into two equal groups (G1 and G2). G1 (control) consisted of 15 patients of both sexes and was treated by exercises therapy program and G2 (experimental) consisted of 15 Parkinsonian patients of both sexes and was treated by the same exercises therapy program and low level pulsed electromagnetic therapy. Vital signs such as blood pressure, body temperature, pulse rate and respiratory rate were measured before and after the treatment sessions. Assessments: Visual analogue scale was used to measure degree of pain. tensiometer was used to measure the muscle power of masseter and pterygoid, the digital goniometer was used to investigate the range of TMJ movement. Moreover, standard electromyography test (EMG) was used to measure the compound muscle action potentials. Statistically the results for all groups were analyzed by t-test to compare the differences between the two groups. The statistical package of social sciences (SPSS, version 10) was used for data processing using the P-value 0.05 as a level of significance. Results showed that there were significant improvements in all variables in G2 only. However, there was a little improvement but not significant in both G1. Therefore, it could be concluded that the use of low level pulsed electro-magnetic therapy combined with exercises program was the good method to control pain of TMJ, in

关键词： Electromagnetic Temporomandibular Joint Parkinsonian Patients Electromyography tensiometer Goniometer Pain and Range of Motion

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