scholarly journals Deformation properties of a subgrade in structures reinforced with full displacement piles

2018 ◽  
Vol 216 ◽  
pp. 01006
Author(s):  
Alexey Lanis ◽  
Denis Razuvaev ◽  
Petr Lomov
Keyword(s):  
Experimental Studies ◽  
Deformation Modulus ◽  
Soil Improvement ◽  
Transport Infrastructure ◽  
Soil Conditions ◽  
Subgrade Soil ◽  
Deformation Properties ◽  
Numerical Simulation Methods ◽  
Improvement Measures ◽  
Weak Subgrades

Construction of transport infrastructure facilities on weak subgrades requires special soil improvement measures. One of the advanced methods for deep subgrade soil compaction is known to be Full Displacement Piles (FDP). The purpose of this paper is to establish dependencies of subgrade deformation properties of a soil body reinforced with full displacement piles on reinforcement parameters and soil conditions. Using numerical simulation methods, the authors identified reinforcement parameters and initial soil indicators that have a significant effect on change in the deformation modulus of the reinforced body in the considered boundary conditions. Results of field experimental studies confirmed the reliability of the newly established relationships and regularities.

Experimental Research on the Engineering Properties of Foam-Improved Red Clay Soil

2011 ◽  
Vol 261-263 ◽  
pp. 1831-1835
Author(s):  
Guo Gang Qiao ◽  
Da Jun Yuan ◽  
Bo Liu
Keyword(s):  
Experimental Research ◽  
Clay Soil ◽  
Soil Improvement ◽  
Engineering Properties ◽  
Screw Conveyor ◽  
Test Results ◽  
X Ray Diffraction ◽  
Shield Tunneling ◽  
Red Clay ◽  
Improvement Measures

Red clay soil is widely distributed in south China, the microstructure of red clay soil was studied applying scanning electron microscopy (SEM), and the X-ray diffraction analysis (XRD) test found that a large number of swelling inducing minerals, for example, montmorillonite, illite-montmorillonite or chlorite-smectite were contained in the red clay soil. Shield tunneling in this kind of stratum is prone to arising “cake” and “arch” phenomena and it prone to lead screw conveyor device unsmooth dumping, so soil improvement measures must be taken. Foam as the most advanced soil conditioner has been widely used in shield construction. Using self-developed foam agent, experimental research on foam conditioning red clay soil was carried out, test results show that foam can not only significantly reduce the soil shear strength, but also can greatly enhance the soil's compressibility and fluidity, which is significant for the smooth dumping and excavation face stability maintenance.

Experimental Studies of Fiber-Reinforced Concrete under Axial Tension

2021 ◽  
Vol 1038 ◽  
pp. 323-329
Author(s):  
Zlata Holovata ◽  
Daria Kirichenko ◽  
Irina Korneeva ◽  
Stepan Neutov ◽  
Marina Vyhnanets
Keyword(s):  
Reinforced Concrete ◽  
Experimental Studies ◽  
Fiber Reinforced Concrete ◽  
Load Application ◽  
Fiber Reinforced ◽  
Large Aggregate ◽  
Second Stage ◽  
Axial Tension ◽  
Deformation Properties ◽  
Fiber Concrete

The design of a stand for testing concrete and fiber-reinforced concrete specimens-"eight" in tension, which provides axial load application and minimizes the effect of stress concentration at the ends of the specimen. The design of the stand is such that the distance between the axis of load application and the central hinge is 108 cm, and between this hinge and the axis of the test specimen is 21 cm, as a result of which the load transferred to the specimen is 5.143 times greater than the applied one. At the first stage of testing, it was found that the optimal characteristics of the fiber-concrete mixture is a matrix with a large aggregate ≤ 10 mm with 1.0% fiber reinforcement. At the second stage, the ultimate strength of fiber-reinforced concrete for axial tension was determined - 1.28 MPa when reinforced with wave fiber and 1.37 MPa when reinforced with anchor fiber, which amounted to 4.1% and 4.4% of compressive strength, respectively. It was also found that concrete reinforced with anchor fiber has higher deformation properties than concrete reinforced with wave fiber.

scholarly journals Deformation of rockfill in bodies of rockfill dams

2019 ◽  
pp. 5-5
Author(s):  
Mikhail Sainov
Keyword(s):  
Reinforced Concrete ◽  
Deformation Modulus ◽  
Deformation Model ◽  
Observation Data ◽  
Linear Deformation ◽  
Laboratory Test Results ◽  
Wide Range ◽  
Deformation Properties ◽  
Non Linear ◽  
The Impact

Introduction. The main factor determining the stress-strain state (SSS) of rockfill dam with reinforced concrete faces is deformability of the dam body material, mostly rockfill. However, the deformation properties of rockfill have not been sufficiently studied yet for the time being due to technical complexity of the matter, Materials and methods. To determine the deformation parameters of rockfill, scientific and technical information on the results of rockfill laboratory tests in stabilometers were collected and analyzed, as well as field data on deformations in the existing rockfill dams. After that, the values of rockfill linear deformation modulus obtained in the laboratory and in the field were compared. The laboratory test results were processed and analyzed to determine the parameters of the non-linear rockfill deformation model. Results. Analyses of the field observation data demonstrates that the deformation of the rockfill in the existing dams varies in a wide range: its linear deformation modulus may vary from 30 to 500 МPа. It was found out that the results of the most rockfill tests conducted in the laboratory, as a rule, approximately correspond to the lower limit of the rockfill deformation modulus variation range in the bodies of the existing dams. This can be explained by the discrepancy in density and particle sizes of model and natural soils. Only recently, results of rockfill experimental tests were obtained which were comparable with the results of the field measurements. They demonstrate that depending on the stress state the rockfill linear deformation modulus may reach 700 МPа. The processing of the results of those experiments made it possible to determine the parameters on the non-linear model describing the deformation of rockfill in the dam body. Conclusions. The obtained data allows for enhancement of the validity of rockfill dams SSS analyses, as well as for studying of the impact of the non-linear character of the rockfill deformation on the SSS of reinforced concrete faces of rockfill dams.

scholarly journals INFLUENCE OF CLAYEY SOIL STRUCTURE ON ITS MODULUS OF STIFFNESS

1999 ◽  
Vol 5 (2) ◽  
pp. 108-115
Author(s):  
Antanas Alikonis
Keyword(s):  
Soil Structure ◽  
Clayey Soil ◽  
Deformation Modulus ◽  
Natural Soil ◽  
Logarithmic Scale ◽  
Compression Curve ◽  
Engineering Structures ◽  
Compacted Soil ◽  
Deformation Properties ◽  
Compressibility Coefficient

Disturbance of soil structure influences its density, strength and deformation properties. Among other cases soil structure could be disturbed by compacting it. It is possible to increase deformation properties of sand or gravel by compacting them. However, for clay soils deformation properties may increase if they are compacted. Differences of settlements of a building depends on the different deformation properties of the artificially placed and compacted soils beneath the foundations. Different values of stiffness modulus are used for the structural design of the buildings which are constructed on the soils with different compressibility. Coefficient of changeability of soil compression (1) was used. It may be calculated as a ratio of maximum and minimum values of deformation modulus, or according to the maximum and minimum values of coefficient of relative compressibility (3). Coefficient of the relative compressibility of soil can be calculated depending on the maximum and minimum values of tip resistence from CPT test (5). According to the coefficient of the relative compressibility we could estimate whether the soil is uniform, nonuniform or extremely non-uniform. It is important for the design of civil engineering structures. Mechanical properties of soils may be back-calculated using theoretical values of settlements and loads. Most frequently within the building layout area soils are natural and artificially compacted. For a compacted soil it is possible to draw compression curve in semi-logarithmic scale using compression curve of the same natural soil and the void ratio of the artificially placed and compacted soil. Thus we can determine compressibility of the soil with disturbed or undisturbed structure. Using parameters of soil compressibility, we can determine the coefficient of the relative compressibility, maximum and minimum values of settlement and modulus of stiffness.

scholarly journals Laboratory Plate Loading Test on Calcareous Sands from a Hydraulic fill Reef Island

2021 ◽  
Author(s):  
Xing Wang ◽  
YANG WU ◽  
Jie Cui ◽  
Chang-qi Zhu ◽  
Xin-zhi Wang
Keyword(s):  
Bearing Capacity ◽  
Deformation Modulus ◽  
Fine Sand ◽  
Medium Sand ◽  
Calcareous Sand ◽  
Loading Test ◽  
Moisture Condition ◽  
Hydraulic Fill ◽  
Deformation Properties ◽  
Plate Loading

Abstract The landforms and vertical strata distribution characteristics of Yongxing Island show that the reclaimed reef island is characterized by soft upper strata (calcareous sand) and hard lower strata (reef limestone). In this study, a series of plate loading tests was conducted to examine the influences of particle gradation, compactness, and moisture condition on the bearing mechanism and deformation properties of the calcareous sand foundation. When the foundation is shallowly buried, the relative density range corresponding to a calcareous sand foundation exhibiting local shear failure is narrower than that of a terrigenous sand foundation. For the same compactness, dry calcareous medium sand has a much larger bearing capacity and deformation modulus than dry calcareous fine sand. The effect of water on the bearing capacity of the calcareous medium sand is greater than the effect on calcareous fine sand. Its weak cementation and low permeability make the initial deformation of saturated calcareous fine sand slightly smaller than that under dry conditions. The stress dispersion angle of the calcareous medium sand foundation is 52°, which is larger than that of terrigenous sand. A larger stress dispersion angle leads to a higher bearing capacity and deformation modulus than those of terrigenous sand.

Features of slopes overcoming by walking devices

2021 ◽  
Vol 9 (3) ◽  
pp. 234-240
Author(s):  
Vadim Chernyshev ◽  
Vladimir Arykantsev ◽  
Anton Goncharov ◽  
Nikolay Sharonov
Keyword(s):  
Mobile Robots ◽  
Experimental Studies ◽  
Field Tests ◽  
Soil Conditions ◽  
Adhesion Properties ◽  
Walking Machines ◽  
Volgograd Region ◽  
Propulsion Unit ◽  
Force Characteristics ◽  
Robot Body

For mobile robots designed to work in extreme conditions, an important characteristic is the value of the overcoming slope. For wheeled and tracked vehicles, the angle of the overcoming slope is limited by the adhesion properties of the soil. The walking device can provide overcoming of higher slopes, since the analogue of the adhesion coefficient for walking machines, with a large footprint track depth, can be significantly greater than 1. The paper discusses the results of experimental studies of the features of overcoming slopes by a walking device in weak soil conditions. When mobile robots overcoming inclines, they may overturn or slide downhill. It is shown that on soft soils the sliding of walking machines downhill is unlikely because of significant deformations of the soil under the support elements. On the other hand, the deformation of the soil worsens the resistance of the walking vehicle to overturning. A method of increasing resistance to overturning by controlling the position of the robot body by separately regulating the conditional clearance of walking mechanisms is considered. The possibility of adjusting the clearance in the propulsion unit on the basis of Umnov-Chebyshev cyclic walking mechanisms is shown. Climbing slopes requires a certain amount of traction. The values of the additional power and the force characteristics of the walking device’s drive necessary for successful overcoming of slopes have been determined. The results of the work can be demand in the development of walking machines and mobile robots. Key words Mobile robots, walking machines, interaction with the ground, traction and coupling properties, overcoming slopes, tipping resistance, mathematical modeling, field tests. Acknowledgements Research was partially supported by RFBR and the Administration of the Volgograd region, research projects no. 19-08-01180 a, 19-48-340007 p_a.

Studies of Magnetically Active Silicone Elastomers on a Vibrostend

2021 ◽  
Vol 1037 ◽  
pp. 141-147
Author(s):  
Andrey Minaev ◽  
Juri Korovkin ◽  
Hammat Valiev ◽  
G.V. Stepanov ◽  
Dmitry Yu. Borin
Keyword(s):  
Magnetic Field ◽  
Field Effect ◽  
Dynamic Properties ◽  
Experimental Studies ◽  
Magnetic Field Effect ◽  
Magnetorheological Elastomer ◽  
Silicone Elastomers ◽  
Damping Coefficients ◽  
Deformation Properties ◽  
The Magnetic Field

Experimental studies magnetorheological elastomer specimens dynamic properties under the magnetic fields action on the vibrostend are carried out. Amplitude-frequency characteristics have been obtained. The magnetic field effect on the silicone magnetoreactive elastomers deformation properties and damping coefficients experimentally is established.

scholarly journals Evaluation of the traffic signal regulation efficiency of crossroads with unstable transport demand by time

2018 ◽  
Vol 170 ◽  
pp. 05013
Author(s):  
Ilya Anisimov ◽  
Anastasia Burakova ◽  
Olga Burakova ◽  
Lyudmila Burakova
Keyword(s):  
Urban Areas ◽  
Experimental Studies ◽  
Idle Time ◽  
Traffic Signal ◽  
Main Direction ◽  
Transport Infrastructure ◽  
Entry And Exit ◽  
Traffic Light ◽  
Traffic Lights ◽  
Inefficient Operation

The article describes the results of the research, whose goal is to assess the effectiveness of the traffic light operation at crossroads with unstable transport demand in terms of time and directions. The modern way of cities development consists in creation of sustainable, and, hence, safe, harmless and comfortable environment for residing. This determines the separation of urban and industrial areas, the creation of transport infrastructure, in particular crossroads, which are equipped with traffic lights. As a rule, it is characterized by unstable transport demand in the direction of entry and exit from the territory of enterprises, which causes an inadvertent increase in the idle time of vehicles in the main direction. In the course of experimental studies, the authors found that the crossroads under consideration are parts of the road network that connect the industrial and urban areas, which causes a high traffic intensity in the main areas. At the same time, the share of ineffective resolving phase for entry and exit from the territory of the enterprise reaches 70-80%, which increases the idle time of vehicles in the main direction. The authors proposed an indicator that characterizes the proportion of inefficient operation of the traffic signal.

Evaluation of Dynamic Behavior of Pile Foundations for Interim Storage Facilities Through Geotechnical Centrifuge Tests

2002 ◽  
Author(s):  
Shizuo Tsurumaki ◽  
Hiroyuki Watanabe ◽  
Akira Tateishi ◽  
Kenichi Horikoshi ◽  
Shunichi Suzuki
Keyword(s):  
Dynamic Behavior ◽  
Experimental Studies ◽  
Centrifuge Modeling ◽  
Pile Foundations ◽  
Soil Conditions ◽  
Confining Stress ◽  
Geotechnical Centrifuge ◽  
Centrifuge Tests ◽  
Interim Storage ◽  
Storage Facilities

In Japan, there is a possibility that interim storage facilities for recycled nuclear fuel resources may be constructed on quaternary layers, rather than on hard rock. In such a case, the storage facilities need to be supported by pile foundations or spread foundations to meet the required safety level. The authors have conducted a series of experimental studies on the dynamic behavior of storage facilities supported by pile foundations. A centrifuge modeling technique was used to satisfy the required similitude between the reduced size model and the prototype. The centrifuge allows a high confining stress level equivalent to prototype deep soils to be generated (which is considered necessary for examining complex pile-soil interactions) as the soil strength and the deformation are highly dependent on the confining stress. The soil conditions were set at as experimental variables, and the results are compared. Since 2000, the Nuclear Power Engineering Corporation (NUPEC) has been conducting these research tests under the auspices on the Ministry of Economy, Trade and Industry of Japan.

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