scholarly journals Review of methods for predicting in situ volume change movement of expansive soil over time

2015 ◽  
Vol 7 (1) ◽  
pp. 73-86 ◽  
Author(s):  
Hana H. Adem ◽  
Sai K. Vanapalli
Keyword(s):  
Volume Change ◽  
Expansive Soil ◽  
Over Time

scholarly journals Influence of Hydrogeochemistry on Tunnel Drainage in Evaporitic Formations: El Regajal Tunnel Case Study (Aranjuez, Spain)

2021 ◽  
Vol 13 (3) ◽  
pp. 1505
Author(s):  
Ignacio Menéndez Pidal ◽  
Jose Antonio Mancebo Piqueras ◽  
Eugenio Sanz Pérez ◽  
Clemente Sáenz Sanz
Keyword(s):  
High Speed ◽  
Civil Engineering ◽  
Saturation Index ◽  
The Subject ◽  
Under Construction ◽  
Underground Flow ◽  
Very High ◽  
Over Time

Many of the large number of underground works constructed or under construction in recent years are in unfavorable terrains facing unusual situations and construction conditions. This is the case of the subject under study in this paper: a tunnel excavated in evaporitic rocks that experienced significant karstification problems very quickly over time. As a result of this situation, the causes that may underlie this rapid karstification are investigated and a novel methodology is presented in civil engineering where the use of saturation indices for the different mineral specimens present has been crucial. The drainage of the rock massif of El Regajal (Madrid-Toledo, Spain, in the Madrid-Valencia high-speed train line) was studied and permitted the in-situ study of the hydrogeochemical evolution of water flow in the Miocene evaporitic materials of the Tajo Basin as a full-scale testing laboratory, that are conforms as a whole, a single aquifer. The work provides a novel methodology based on the calculation of activities through the hydrogeochemical study of water samples in different piezometers, estimating the saturation index of different saline materials and the dissolution capacity of the brine, which is surprisingly very high despite the high electrical conductivity. The circulating brine appears unsaturated with respect to thenardite, mirabilite, epsomite, glauberite, and halite. The alteration of the underground flow and the consequent renewal of the water of the aquifer by the infiltration water of rain and irrigation is the cause of the hydrogeochemical imbalance and the modification of the characteristics of the massif. These modifications include very important loss of material by dissolution, altering the resistance of the terrain and the increase of the porosity. Simultaneously, different expansive and recrystallization processes that decrease the porosity of the massif were identified in the present work. The hydrogeochemical study allows the evolution of these phenomena to be followed over time, and this, in turn, may facilitate the implementation of preventive works in civil engineering.

A 3D mixed ion/electron conducting scaffold by in-situ conversion for long-life lithium metal anodes

Nanoscale ◽  
2021 ◽  
Author(s):  
Huai Jiang ◽  
Qingyuan Dong ◽  
Maohui Bai ◽  
Furong Qin ◽  
Maoyi Yi ◽  
...  
Keyword(s):  
Anode Material ◽  
Volume Change ◽  
Specific Energy ◽  
Dendrite Growth ◽  
Commercial Application ◽  
Lithium Metal ◽  
Lithium Metal Anodes ◽  
Long Life ◽  
Metal Anodes

Lithium (Li) metal is widely considered as the most promising anode material because of ultrahigh specific energy. However, obvious volume change and uncontrollable dendrite growth hinder its commercial application. Herein,...

scholarly journals In Situ Production of Zoospores by Five Species of Phytophthora in Aqueous Environments for Use as Inocula

Plant Disease ◽  
2014 ◽  
Vol 98 (4) ◽  
pp. 551-558 ◽  
Author(s):  
G. A. Ridge ◽  
S. N. Jeffers ◽  
W. C. Bridges ◽  
S. A. White
Keyword(s):  
Laboratory Experiment ◽  
Constructed Wetlands ◽  
Aquatic Plant ◽  
Phytophthora Cinnamomi ◽  
Soil Extract ◽  
Greenhouse Experiment ◽  
Zoospore Release ◽  
Aqueous Environments ◽  
Over Time

The goal of this study was to develop a procedure that could be used to evaluate the potential susceptibility of aquatic plants used in constructed wetlands to species of Phytophthora commonly found in nurseries. V8 agar plugs from actively growing cultures of three or four isolates of Phytophthora cinnamomi, P. citrophthora, P. cryptogea, P. nicotianae, and P. palmivora were used to produce inocula. In a laboratory experiment, plugs were placed in plastic cups and covered with 1.5% nonsterile soil extract solution (SES) for 29 days, and zoospore presence and activity in the solution were monitored at 2- or 3-day intervals with a rhododendron leaf disk baiting bioassay. In a greenhouse experiment, plugs of each species of Phytophthora were placed in plastic pots and covered with either SES or Milli-Q water for 13 days during both summer and winter months, and zoospore presence in the solutions were monitored at 3-day intervals with the baiting bioassay and by filtration. Zoospores were present in solutions throughout the 29-day and 13-day experimental periods but consistency of zoospore release varied by species. In the laboratory experiment, colonization of leaf baits decreased over time for some species and often varied among isolates within a species. In the greenhouse experiment, bait colonization decreased over time in both summer and winter, varied among species of Phytophthora in the winter, and was better in Milli-Q water. Zoospore densities in solutions were greater in the summer than in the winter. Decreased zoospore activities for some species of Phytophthora were associated with prolonged temperatures below 13 or above 30°C in the greenhouse. Zoospores from plugs were released consistently in aqueous solutions for at least 13 days. This procedure can be used to provide in situ inocula for the five species of Phytophthora used in this study so that aquatic plant species can be evaluated for potential susceptibility.

scholarly journals Identifying Spatial and Temporal Variations in Concrete Bridges with Ground Penetrating Radar Attributes

2021 ◽  
Vol 13 (9) ◽  
pp. 1846
Author(s):  
Vivek Kumar ◽  
Isabel M. Morris ◽  
Santiago A. Lopez ◽  
Branko Glisic
Keyword(s):  
Compressive Strength ◽  
Ground Penetrating Radar ◽  
Material Properties ◽  
Temporal Variations ◽  
Concrete Bridges ◽  
Spatial And Temporal Variation ◽  
Reflected Waves ◽  
Ground Penetrating ◽  
Over Time

Estimating variations in material properties over space and time is essential for the purposes of structural health monitoring (SHM), mandated inspection, and insurance of civil infrastructure. Properties such as compressive strength evolve over time and are reflective of the overall condition of the aging infrastructure. Concrete structures pose an additional challenge due to the inherent spatial variability of material properties over large length scales. In recent years, nondestructive approaches such as rebound hammer and ultrasonic velocity have been used to determine the in situ material properties of concrete with a focus on the compressive strength. However, these methods require personnel expertise, careful data collection, and high investment. This paper presents a novel approach using ground penetrating radar (GPR) to estimate the variability of in situ material properties over time and space for assessment of concrete bridges. The results show that attributes (or features) of the GPR data such as raw average amplitudes can be used to identify differences in compressive strength across the deck of a concrete bridge. Attributes such as instantaneous amplitudes and intensity of reflected waves are useful in predicting the material properties such as compressive strength, porosity, and density. For compressive strength, one alternative approach of the Maturity Index (MI) was used to estimate the present values and compare with GPR estimated values. The results show that GPR attributes could be successfully used for identifying spatial and temporal variation of concrete properties. Finally, discussions are presented regarding their suitability and limitations for field applications.

An SiOx anode strengthened by the self-catalytic growth of carbon nanotubes

Nanoscale ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 3808-3816
Author(s):  
Hongjin Xue ◽  
Yong Cheng ◽  
Qianqian Gu ◽  
Zhaomin Wang ◽  
Yabin Shen ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Volume Change ◽  
Large Volume ◽  
The Self ◽  
Catalytic Growth ◽  
Large Volume Change

A close-knit CNTs coating that in-situ grown on the SiOx particles realizes the “soft-combination” between SiOx and CNTs, thus conquering the long-lasting issues of poor conductivity and large volume change of SiOx faced.

Understanding Volume Change in Lithium-Ion Cells during Charging and Discharging Using In Situ Measurements

2007 ◽  
Vol 154 (1) ◽  
pp. A14 ◽  
Author(s):  
Xianming Wang ◽  
Yoshitsugu Sone ◽  
Go Segami ◽  
Hitoshi Naito ◽  
Chisa Yamada ◽  
...  
Keyword(s):  
Volume Change ◽  
Lithium Ion ◽  
In Situ Measurements ◽  
Lithium Ion Cells

scholarly journals The Use of Geogrids in Mitigating Pavement Defects on Roads Built over Expansive Soils

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Richard Shumbusho ◽  
Gurmel S. Ghataora ◽  
Michael P.N. Burrow ◽  
Digne R. Rwabuhungu
Keyword(s):  
Seasonal Changes ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Real Field ◽  
Experimental Program ◽  
Swelling Potential ◽  
Swelling Behaviour ◽  
Wetting And Drying ◽  
Potential Benefits

This study was conducted to investigate the potential benefits of using geogrids in mitigating pavement defects notably roughness and longitudinal cracking on pavements built over expansive soils. The seasonal changes of expansive soils (periodic wetting and drying) cause detrimental effects on the overlying road pavements. Such detrimental behavior of expansive soils was simulated in a controlled laboratory environment through allowing cyclic wetting and drying of an expansive soil underlying a pavement section. The shrink/swell effects of the expansive soil subgrade were examined through monitoring its change in moisture, and measuring deformation of overlying pavement section. The experimental study suggested that a geogrid layer in a reinforced pavement section can reduce surface differential shrinking and swelling deformation resulting from underlying expansive soils by a factor of 2 and 3 respectively in comparison to unreinforced section. Given that an oedometer test which is typically used to predict swelling potential of expansive soils is known to overpredict in-situ soil swell, experimental program also investigated quantitatively the extent to which the oedometer can overestimate swelling behaviour of the real-field scenarios. It was found that oedometer percent swell can overpredict in-situ swelling behaviour of the expansive soil by a factor ranging between 2 and 10 depending upon the period over which the in-situ expansive soil has been in contact with water.

In Situ Observation of Phase Transformations during Welding of Low Transformation Temperature Filler Material

2010 ◽  
Vol 638-642 ◽  
pp. 3769-3774 ◽  
Author(s):  
Arne Kromm ◽  
Thomas Kannengiesser ◽  
Jens Gibmeier
Keyword(s):  
Residual Stresses ◽  
Phase Transformations ◽  
Volume Change ◽  
Transformation Temperature ◽  
High Energy ◽  
Filler Materials ◽  
Transformation Temperatures ◽  
Welding Processes ◽  
Compressive Residual Stresses

Tensile residual stresses introduced by conventional welding processes diminish the crack resistance and the fatigue lifetime of welded components. In order to generate beneficial compressive residual stresses at the surface of a welded component, various post-weld treatment procedures are available, like shot peening, hammering, etc. These post-weld treatments are, however time and cost extensive. An attractive alternative is to generate compressive stresses over the complete weld joint in the course of the welding procedure by means of so-called Low Transformation Temperature (LTT) filler materials. The volume change induced by the transformation affects the residual stresses in the weld and its vicinity. LTT fillers exhibit a relatively low transformation temperature and a positive volume change, resulting in compressive residual stresses in the weld area. In-situ measurements of diffraction profiles during real welding experiments using Gas Tungsten Arc (GTA)-welding process were realized successfully for the first time. Transformation temperatures during heating and subsequent cooling of LTT welding material could be assessed by means of energy dispersive diffraction using high energy synchrotron radiation. The results show that the temperature of martensite start (Ms) is strongly dependent on the content of alloying elements. In addition the results indicate that different phase transformation temperatures are present depending on the welding depth. Additional determination of residual stresses allowed it to pull together time and temperature resolved phase transformations and the resulting phase specific residual stresses. It was shown, that for the evaluation of the residual stress state of LTT welds the coexisting martensitic and austenitic phases have to be taken into account when describing the global stress condition of the respective material in detail.

Optimizing Preloading Pressure of Precharged Gas for Isobaric Gas-Tight Hydrothermal Samplers

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Haocai Huang ◽  
Liang Huang ◽  
Wei Ye ◽  
Shijun Wu ◽  
Canjun Yang ◽  
...  
Keyword(s):  
Volume Change ◽  
Theoretical Models ◽  
Sample Volume ◽  
Field Application ◽  
Laboratory Simulation ◽  
Application Process ◽  
Sampling Depth ◽  
Ambient Temperatures ◽  
Gas Tight

Isobaric gas-tight hydrothermal samplers, with the ability to maintain pressure, can be used to keep in situ chemical and biological sample properties stable. The preloading pressure of the precharged gas is a major concern for isobaric gas-tight hydrothermal samplers, especially when the samplers are used at different sampling depths, where the in situ pressures and ambient temperatures vary greatly. The most commonly adopted solution is to set the preloading pressure for gas-tight samplers as 10% of the hydrostatic pressure at the sampling depth, which might emphasize too much on pressure retention; thereby, the sample volume may be unnecessarily reduced. The pressure transition of the precharged gas was analyzed theoretically and modeled at each sampling stage of the entire field application process. Additionally, theoretical models were built to represent the pressure and volume of hydrothermal fluid samples as a function of the preloading pressure of the precharged gas. Further, laboratory simulation and examination approaches were also adopted and compared, in order to obtain the volume change of the sample and accumulator chambers. By using theoretical models and the volume change of the two chambers, the optimized preloading pressure for the precharged gas was obtained. Under the optimized preloading pressure, the in situ pressure of the fluid samples could be maintained, and their volume was maximized. The optimized preloading pressure obtained in this study should also be applicable to other isobaric gas-tight hydrothermal samplers, by adopting a similar approach to pressure maintenance.

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