scholarly journals Field Test and Numerical Simulation for Coordinated Deformation of New Subgrade and Old Embankment Adjacent to River

2018 ◽  
Vol 8 (12) ◽  
pp. 2334 ◽  
Author(s):  
Jihong Wei ◽  
Zezhuo Song ◽  
Yuxia Bai ◽  
Jin Liu ◽  
Debi Kanungo ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Research Work ◽  
Drainage System ◽  
Field Tests ◽  
Creep Model ◽  
Soft Ground ◽  
Band Model ◽  
In Situ Tests ◽  
Wall Model

With the development of the economy in China, original roads may be unable to cope with the existing traffic. The expansion of the old embankment is the core problem for road expansion. Soft foundation differential settlements and pavement cracking along the joint between the new subgrade and old embankment often emerge after construction, especially during the operational period of the road. The Binjiang Avenue Project in Nanjing, China, is taken as a research example in this paper, and a typical test zone of about 300.0 m in length was selected to conduct research work through in-situ tests. The coordinated deformations of the subgrade combined with the old embankment under conditions of consolidation by drainage were researched using in-situ tests and numerical modeling. During the process of numerical modeling, the vertical drainage system in the compressible soft ground layers was simplified to be represented as the drainage band model and the equivalent sand-wall model. In addition, a soft ground creep model was adopted to calculate the deformation of the subgrade with the construction process. A comparison of the results between field tests and numerical simulations was carried out. The results show that there is good uniformity for both. Based on the results, three indexes for the new and old subgrade, such as the differential settlement, total settlement and post-settlement, should be viewed as the basis for the design and construction of the new subgrade and old embankment. Additionally, it was found that the soft ground model, drainage band model and equivalent sand-wall model are all completely suitable for the numerical modeling of the soft ground reinforcement subgrade. These results also provide a theoretical basis for the construction method of similar projects.

scholarly journals Determination of p-y curves for offshore piles based on in-situ soil investigations

2018 ◽  
Vol 219 ◽  
pp. 05003
Author(s):  
Kamila Międlarz ◽  
Lech Bałachowski
Keyword(s):  
Field Tests ◽  
Soil Parameters ◽  
Lateral Loads ◽  
Cohesionless Soils ◽  
In Situ Tests ◽  
Soil Stiffness ◽  
Soil Response ◽  
Direct Design ◽  
Offshore Piles

Offshore piles are subjected to complex loads with considerable lateral component. The pile-soil response to lateral loads can be described with the p-y method. For a given depth the load–deflection relationship is built to simulate the surrounding soil stiffness. This state-of-art paper presents a brief discussion of determination methods for the p-y curves using a standard approach based on the soil parameters derived from laboratory and in-situ tests or directly from field tests. The basic relationships for both cohesive and cohesionless soils are discussed. The advantage of direct design methods to describe the p-y curve relies in the reduction of necessary laboratory tests.

scholarly journals Improvement of Gas Drainage Efficiency via Optimization of Sealing Depth of Cross-Measure Boreholes

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Pu Li ◽  
Zhiheng Cheng ◽  
Liang Chen ◽  
Hongbing Wang ◽  
Jialin Cao
Keyword(s):  
Stress Concentration ◽  
Drainage System ◽  
Stress Concentration Zone ◽  
Concentration Zone ◽  
Air Leakage ◽  
In Situ Tests ◽  
Gas Drainage ◽  
Drainage Borehole

The sealing depth of a gas-drainage borehole is critically important as it directly affects the efficiency of the whole drainage system. In order to determine the shortest reasonable sealing depth, in this paper, a theoretical drainage model using different sealing depths was proposed. Based on theoretical analysis presented, two parts of the fractures system surrounding the drainage borehole were proposed, i.e. the fractures induced by roadway excavation and the fractures induced by borehole drilling. A series of geological in-situ tests and simulations research were conducted to determine the stress and fracture distributions in the surrounding rock of the borehole. The depths of crushing zones, plastic zones and stress concentration zones were determined as 5 m, 2 m and 12 m, respectively. Meanwhile, stress simulation shows that the depth of the stress concentration zone was 12 m from the roadway wall and the stress peak was located at the depth of 8 m, which can be verified by the results of drilling penetration velocity analysis. To determine the optimum sealing depth, gas drainage holes with different sealing depths were drilled in the field. The field results revealed that the crushing zones were the main area for air leakage, and the stress concentration induced by roadway excavation assisted in the reduction of air leakage. Therefore, the optimized sealing depth should both cover the plastic zone and the stress concentration zone. The research achievements can provide a quantitative method for the determination of optimum sealing depth in cross-measure drainage boreholes.

scholarly journals Evaluation of Stiffness Degradation Curves from in Situ Tests in Various Soil Types

2018 ◽  
Vol 64 (4) ◽  
pp. 285-307
Author(s):  
T. Godlewski
Keyword(s):  
Field Tests ◽  
Shear Stiffness ◽  
Test Methods ◽  
Soil Types ◽  
Design Parameters ◽  
Design Calculation ◽  
In Situ Tests ◽  
Nonlinearity Test ◽  
Strain Dependent

AbstractIncreasingly complex design systems require an individual approach when determining the necessary design parameters. As soils are characterized by strong strain-dependent nonlinearity, test methods used to characterize the subsoil should be carefully selected, in terms of their “sensitivity” as well as suitability for the analyzed type of problem. When direct measurements are not available, while design calculation models require specific parameters, indirect parameter estimation may be used. This approach requires calibration and validation of empirical correlations, based on well documented database of tests and case studies. One of the parameters often used, when analyzing soil-structure interaction problems, is the shear stiffness of the soil and its strain-dependent degradation. The aim of the article is to present the procedure for description and evaluation of soil stiffness based on field tests (CPTU, DMT and SDMT) and a large number of reference curves obtained from laboratory tests (TRX) for selected soil types. On the basis of the given algorithm, it is possible to obtain a stiffness module G0 value at any level of deformation, based on in-situ tests.

A geotechnical investigation of marine deposits in a nearshore seabed for land reclamation

1999 ◽  
Vol 36 (6) ◽  
pp. 981-1000 ◽  
Author(s):  
Kin-Man Lee ◽  
Patrick CC Ng
Keyword(s):  
Land Reclamation ◽  
Large Diameter ◽  
Field Tests ◽  
In Situ Tests ◽  
Coefficient Of Consolidation ◽  
Marine Deposits ◽  
Undisturbed Samples ◽  
Horizontal Drainage ◽  
Rowe Cell

The properties of marine deposits in a nearshore seabed at a land reclamation site in Hong Kong were investigated. A variety of laboratory and in situ tests were conducted to define the geotechnical and consolidation characteristics of the marine deposits. The reliability and applicability of various laboratory and in situ testing techniques in evaluating the coefficient of consolidation were examined. Coefficients of consolidation were calculated from conventional oedometer tests, large-diameter (250 mm) Rowe cell tests, field permeability tests, and piezocone dissipation tests. Three techniques were adopted to evaluate the horizontal coefficient of consolidation ch from the results of in situ piezocone dissipation tests. Results from in situ pore pressure dissipation tests are compared with those from large-diameter Rowe cell tests performed on undisturbed samples under both vertical and horizontal drainage conditions and in situ permeability tests to provide reference values of the vertical coefficient of consolidation cv and ch. The engineering implications, particularly those related to land reclamation work in the nearshore environment, of various laboratory and field tests are discussed.

scholarly journals Experimental and CFD Simulations of the Aerosol Flow in the Air Ventilating the Underground Excavation in Terms of SARS-CoV-2 Transmission

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4743
Author(s):  
Tomasz Janoszek ◽  
Zbigniew Lubosik ◽  
Lucjan Świerczek ◽  
Andrzej Walentek ◽  
Jerzy Jaroszewicz
Keyword(s):  
Numerical Calculations ◽  
Mining Institute ◽  
Ventilation Network ◽  
Underground Excavation ◽  
In Situ Tests ◽  
Ansys Fluent ◽  
Aerosol Emission ◽  
Ansys Cfx ◽  
Computational Fluid Dynamics Cfd

The paper presents the results of experimental and model tests of transport of dispersed fluid droplets forming a cloud of aerosol in a stream of air ventilating a selected section of the underground excavation. The excavation selected for testing is part of the ventilation network of the Experimental Mine Barbara of the Central Mining Institute. For given environmental conditions, such as temperature, pressure, relative humidity, and velocity of air, the distribution of aerosol droplet changes in the mixture of air and water vapor along the excavation at a distance was measured at 10 m, 25 m, and 50 m from the source of its emission. The source of aerosol emission in the excavation space was a water nozzle that was located 25 m from the inlet (inlet) of the excavation. The obtained results of in situ tests were related to the results of numerical calculations using computational fluid dynamics (CFD). Numerical calculations were performed using Ansys-Fluent and Ansys-CFX software. The dimensions and geometry of the excavation under investigation are presented. The authors describe the adopted assumptions and conditions for the numerical model and discuss the results of the numerical solution.

scholarly journals Experimental Evaluation of Shear Behavior of Stone Masonry Wall

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2313
Author(s):  
Maria Luisa Beconcini ◽  
Pietro Croce ◽  
Paolo Formichi ◽  
Filippo Landi ◽  
Benedetta Puccini
Keyword(s):  
Shear Behavior ◽  
Stone Masonry ◽  
Masonry Walls ◽  
Mechanical Parameters ◽  
In Situ Tests ◽  
Capacity Curves ◽  
Historical Structures ◽  
Definition Of

The evaluation of the shear behavior of masonry walls is a first fundamental step for the assessment of existing masonry structures in seismic zones. However, due to the complexity of modelling experimental behavior and the wide variety of masonry types characterizing historical structures, the definition of masonry’s mechanical behavior is still a critical issue. Since the possibility to perform in situ tests is very limited and often conflicting with the needs of preservation, the characterization of shear masonry behavior is generally based on reference values of mechanical properties provided in modern structural codes for recurrent masonry categories. In the paper, a combined test procedure for the experimental characterization of masonry mechanical parameters and the assessment of the shear behavior of masonry walls is presented together with the experimental results obtained on three stone masonry walls. The procedure consists of a combination of three different in situ tests to be performed on the investigated wall. First, a single flat jack test is executed to derive the normal compressive stress acting on the wall. Then a double flat jack test is carried out to estimate the elastic modulus. Finally, the proposed shear test is performed to derive the capacity curve and to estimate the shear modulus and the shear strength. The first results obtained in the experimental campaign carried out by the authors confirm the capability of the proposed methodology to assess the masonry mechanical parameters, reducing the uncertainty affecting the definition of capacity curves of walls and consequently the evaluation of seismic vulnerability of the investigated buildings.

scholarly journals Underwater Holographic Sensor for Plankton Studies In Situ Including Accompanying Measurements

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4863
Author(s):  
Victor Dyomin ◽  
Alexandra Davydova ◽  
Igor Polovtsev ◽  
Alexey Olshukov ◽  
Nikolay Kirillov ◽  
...  
Keyword(s):  
World Ocean ◽  
Field Tests ◽  
Field Measurements ◽  
Measuring Systems ◽  
Water Turbidity ◽  
Background Data ◽  
Average Size ◽  
Size Dispersion

The paper presents an underwater holographic sensor to study marine particles—a miniDHC digital holographic camera, which may be used as part of a hydrobiological probe for accompanying (background) measurements. The results of field measurements of plankton are given and interpreted, their verification is performed. Errors of measurements and classification of plankton particles are estimated. MiniDHC allows measurement of the following set of background data, which is confirmed by field tests: plankton concentration, average size and size dispersion of individuals, particle size distribution, including on major taxa, as well as water turbidity and suspension statistics. Version of constructing measuring systems based on modern carriers of operational oceanography for the purpose of ecological diagnostics of the world ocean using autochthonous plankton are discussed. The results of field measurements of plankton using miniDHC as part of a hydrobiological probe are presented and interpreted, and their verification is carried out. The results of comparing the data on the concentration of individual taxa obtained using miniDHC with the data obtained by the traditional method using plankton catching with a net showed a difference of no more than 23%. The article also contains recommendations for expanding the potential of miniDHC, its purpose indicators, and improving metrological characteristics.

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