scholarly journals Mechanical Characteristic and Length Optimization of System Anchor in Loess Tunnel Based on Field Measurement and Analytical Solution

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zhongming Su ◽  
Jianxun Chen ◽  
Yanbin Luo
Keyword(s):  
Analytical Solution ◽  
Axial Force ◽  
Field Measurement ◽  
Test Results ◽  
Long Span ◽  
Pull Out ◽  
Zone Radius ◽  
Primary Support ◽  
Length Optimization ◽  
Different Parts

In this paper, field measurement is used to obtain the force of system anchor in its actual working condition and stress situation of system anchors in different parts of loess tunnel is analyzed based on field test results, indicating the reasons why values of measured axial force of system anchor are different in different parts of loess tunnel. Based on the displacement solution of Mindlin problem, this paper deduces the analytical solution to stress distribution of system anchors in the sidewall of loess tunnel under the pull-out force, analyzes the distribution forms and influencing factors of shear stress and axial force. At the same time, analytical solutions to system anchor stress and surrounding rock plastic zone radius are tentatively applied to the analysis of stress characteristics and length optimization of system anchor in loess tunnel. The research results are of great significance to understand the mechanical characteristics of anchors in loess tunnel and to optimize the design of anchors in the primary support system of loess tunnel, which leads to accelerated construction progress and low economically cost, especially in loess tunnels with large cross section and long span.

scholarly journals Theoretical analysis and experimental research on multi-layer elastic damping track structure

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199497
Author(s):  
Guanghui Xu ◽  
Shengkai Su ◽  
Anbin Wang ◽  
Ruolin Hu
Keyword(s):  
Finite Element ◽  
Analytical Solution ◽  
Finite Element Simulation ◽  
Reaction Force ◽  
Vibration Reduction ◽  
Vertical Direction ◽  
Propagation Path ◽  
Track Structure ◽  
Test Results ◽  
Element Simulation

The increase of axle load and train speed would cause intense wheelrail interactions, and lead to potential vibration related problems in train operation. For the low-frequency vibration reduction of a track system, a multi-layer track structure was proposed and analyzed theoretically and experimentally. Firstly, the analytical solution was derived theoretically, and followed by a parametric analysis to verify the vibration reduction performance. Then, a finite element simulation is carried out to highlight the influence of the tuned slab damper. Finally, the vibration and noise tests are performed to verify the results of the analytical solution and finite element simulation. As the finite element simulation indicates, after installation of the tuned slab damper, the peak reaction force of the foundation can be reduced by 60%, and the peak value of the vertical vibration acceleration would decrease by 50%. The vibration test results show that the insertion losses for the total vibration levels are 13.3 dB in the vertical direction and 21.7 dB in the transverse direction. The noise test results show that the data of each measurement point is smoother and smaller, and the noise in the generating position and propagation path can be reduced by 1.9 dB–5.5 dB.

Inclined Loading Capacity of Embedded Suction Anchors in Clay

2009 ◽  
Author(s):  
Y. S. Kim ◽  
K. O. Kim ◽  
Y. Cho ◽  
S. Bang ◽  
K. D. Jones
Keyword(s):  
Analytical Solution ◽  
Model Test ◽  
Inclination Angle ◽  
Load Application ◽  
Centrifuge Model Test ◽  
Loading Capacity ◽  
Test Results ◽  
Pullout Capacity ◽  
Centrifuge Model ◽  
Inclined Loading

An analytical solution has been developed to estimate the inclined pullout capacity of an embedded suction anchor in clay seafloor. Validation has been made through comparisons with a limited number of centrifuge model test results. Results indicate that the inclined pullout capacity of an embedded suction anchor in clay decreases as the load inclination angle to the horizontal increases. As the point of the load application moves downward, the inclined pullout capacity increases, reaches its peak, and then starts to decrease.

Analysis of Plastic-Zone Radius Influenced by Mechanical Parameters in Tunnel Excavation and Support

2012 ◽  
Vol 238 ◽  
pp. 787-790
Author(s):  
Zhong Ming Su ◽  
Rui Liu
Keyword(s):  
Plastic Zone ◽  
Axial Force ◽  
Analytical Formula ◽  
Mechanical Parameters ◽  
Circular Tunnel ◽  
Tunnel Excavation ◽  
Dynamic Design ◽  
Elastic Plastic ◽  
Zone Radius ◽  
Plastic Theory

According to the elastic-plastic theory, the analytical formula of plastic zone radius is established for circular tunnel in its excavation and support, and the effect of anchor support is verified based on the radius of plastic zone from the perspective of measured axial force. The influences to plastic zone by the variations of mechanical parameters and resistance of support are quantitatively analyzed. The result is of great significance to the monitoring measurement and the dynamic design and construction of tunnel.

Interaction Between Impeller and Volute of Pumps at Off-Design Conditions

1986 ◽  
Vol 108 (1) ◽  
pp. 12-18 ◽  
Author(s):  
J. A. Lorett ◽  
S. Gopalakrishnan
Keyword(s):  
Analytical Solution ◽  
Flow Behavior ◽  
Cyclic Variation ◽  
Test Results ◽  
Flow Parameters ◽  
Pump Output ◽  
Simplifying Assumptions ◽  
Radial Thrust ◽  
Relative Flow ◽  
Good Agreement

In a centrifugal pump of volute type, the respective characteristics of the impeller and the volute are such that at only one operating point can the flow parameters be constant along the length of the volute. At off-design conditions the mismatching of characteristics causes variations of velocity and pressure along the periphery of the impeller. This in turn forces cyclic variation of the flow in the impeller channels, introduces variations of the inlet incidence and contributes significantly to the direction and the magnitude of the radial thrust. Furthermore, below a certain pump output, a complete flow reversal occurs over a part of the impeller periphery, thus explaining the onset of recirculation. The paper describes the calculation approach used to derive this aspect of the flow behavior. Because of difficulties in obtaining a closed analytical solution, a step by step computation is employed. Beginning with arbitrarily chosen conditions at the volute tongue, the program computes the flow parameters for following segments, using the continuity and the momentum equations, until the exit from the last segment is reached. The inherent unsteadiness of the relative flow in the impeller is explicitly accounted for. Since the inflow and the velocity in the first segment depend upon the exit conditions of the last, the initial input must be modified, and the computation repeated, until the values are compatible with the exit conditions. In spite of several simplifying assumptions, the results of the calculations show very good agreement with published test results.

Influence of Silane Coupling Agent on Interfacial Strength of SMA Composite

2010 ◽  
Vol 143-144 ◽  
pp. 933-937
Author(s):  
Yu Long Wang ◽  
Zhen Qing Wang ◽  
Li Min Zhou ◽  
Hai Tao Huang
Keyword(s):  
Coupling Agent ◽  
Shape Control ◽  
Silane Coupling Agent ◽  
Interfacial Strength ◽  
Test Results ◽  
Surrounding Matrix ◽  
Pull Out ◽  
Damage Repair ◽  
Silane Coupling ◽  
Epoxy Matrix Composite

Shape memory alloy (SMA) can be embedded into a host material to achieve shape control, damage repair and self-adaption. It is well recognized that the applications of SMA composites are highly dependent on the integrity of SMA fiber-matrix interface. However, the interfacial debonding often occurs due to the weak bonding of interface between the SMA wire and its surrounding matrix. Therefore, it is necessary to improve interfacial strength of SMA composites. In present paper, the epoxy resin is functionalized by mixing different amount of silane coupling agent to improve the interfacial adhesion of SMA fiber reinforced epoxy matrix composite. The single fiber pull-out test is carried out to evaluate the interfacial strength and the test results indicate that the interfacial strength of SMA composite is improved significantly as compared to the results from unfunctionalized samples.

Bond of Steel Bars to Masonry Mortar Joints: Test Results and Analytical Modelling

2017 ◽  
Vol 747 ◽  
pp. 319-325 ◽  
Author(s):  
Matteo Maragna ◽  
Cristina Gentilini ◽  
Giovanni Castellazzi ◽  
Christian Carloni
Keyword(s):  
High Strength ◽  
Experimental Tests ◽  
Analytical Investigation ◽  
Masonry Walls ◽  
Test Results ◽  
Bond Slip ◽  
Pull Out ◽  
Steel Bars ◽  
Masonry Mortar

In this paper, the preliminary results of a series of pull-out tests conducted on mortar cylinders with embedded bars are presented. The bars are made of high strength stainless steel and are of helical shape to increase mechanical interlocking with the surrounding mortar. Usually, such bars are employed in situ to realize structural repointing in the case of fair-faced masonry walls. To this aim, they are inserted in the mortar bed joints of masonry for providing tensile strength to the walls and with the function of crack stitching. The aim of the present experimental tests is to determine the bond-slip relationship for bars embedded in masonry. Firstly, pull-out tests are conducted on mortar cylinders considering different embedded lengths of the bars. Further tests are on-going on masonry specimens with bars embedded in the mortar joints. An analytical investigation is also carried out for the interpretation of the pull-out test results.

scholarly journals The Influence of Pile-Driving Vibration on the Soil Nailing Support of a Silty Soil Foundation Pit

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Yuancheng Guo ◽  
Hao Wu ◽  
Chenglin Li
Keyword(s):  
Axial Force ◽  
Soil Strength ◽  
Interface Strength ◽  
Pile Driving ◽  
Vibration Exciter ◽  
Foundation Pit ◽  
Soil Nail ◽  
Pull Out ◽  
Working Length ◽  
Soil Interface

The ground vibration induced by pile driving affects the safety of the adjacent foundation pit. In this paper, the influence of pile-driving vibration on the soil strength and the nail-soil interface strength was studied, and the variation in the axial force and displacement of the soil nail under vibration was analyzed. The paper studied the effects under different vibration parameters on the soil strength and the nail-soil interface strength by using a vibration exciter and a nail pull-out model box. The results showed that the stronger the excitation force was and the higher the frequency was, the greater the attenuation of the soil strength and nail-soil interface strength was. On the contrary, the change of the internal friction angle of the soil was not obvious under the vibration. The nail-soil interface strength recovered when the vibration terminated. Decreases in c and τp led to an increase in the working length of the soil nail, a redistribution of the axial force, and an augmentation in the soil nail displacement.

scholarly journals Application of Analytical Solution to Steady-State Temperature Field by Double-Row-Pipe Freezing and Verification with Field Measurement: A Case Study of Connected Aisle

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Zequn Hong ◽  
Xiangdong Hu
Keyword(s):  
Temperature Field ◽  
Steady State ◽  
Analytical Solution ◽  
Wall Thickness ◽  
Field Measurement ◽  
Field Analysis ◽  
Shield Tunnel ◽  
Double Row ◽  
Steady State Temperature ◽  
Frozen Wall

In order to solve the problem of sealing water and bearing capacity of a connected aisle in an underwater shield tunnel, a double-circle horizontal freezing method was adopted for ground reinforcement in the connected aisle of Maliuzhou Tunnel, which is China’s first shield tunnel with superlarge diameter built in a composite stratum. This paper proposed a new double-row-pipe freezing model for the calculation of frozen wall thickness based on analytical solution to steady-state temperature field. Besides, field measurement and transient numerical studies of the active freezing period were also carried out to study the freeze-sealing effect. The results show that frozen wall thickness obtained by analytical solutions agrees well with numerical simulation results, which verifies the applicability of the newly proposed calculation method. Field analysis indicates that soil temperature gradually approaches a stable value which is far below the freezing point, and a reliable water-sealing curtain can be formed around the designed connected aisle. Maximum impact of soil excavation on the frozen wall is about 10°C, and reducing exposure time of excavation surface can effectively alleviate the weakening of frozen wall. To obtain comprehensive analysis for freezing wall thickness, a more reasonable arrangement of temperature-measuring holes is expected in future freezing engineering.

PULL OUT STRENGTH FOR DIFFERENT SIZE OF DOWEL AND GRAIN DIRECTION OF GLULAM

2016 ◽  
Vol 78 (5-4) ◽  
Author(s):  
Tengku Anita Raja Hussin ◽  
Mohamad Iswandi Jinne ◽  
Rohana Hassan
Keyword(s):  
Failure Modes ◽  
Maximum Load ◽  
Experimental Program ◽  
Drilling Process ◽  
Test Results ◽  
Bond Behaviour ◽  
Pull Out ◽  
Timber Joints ◽  
Different Thickness ◽  
Pull Out Strength

This paper presents an experimental program for testing glued-in dowel glulam timber joints. Hundred thirty glulam specimens, each with a single glued-in rebar parallel to the grain and perpendicular to grain with different size of dowels 12mm, 16mm and 20mm were tested to evaluate the effects of anchorage length and different dowel diameter for parallel and perpendicular to the grain on pull-out strength and bond behaviour of glued-in rebar timber joints. The test results showed that the maximum load for specimen with dowel glued-in parallel to the grain given the higher maximum load than dowel glued-in perpendicular to the grain direction. Failure modes were characterized by pull out failure in the mode of adhesive-dowel, yet one sample failed in timber-adhesive mode. This might happened because the surface of the timber was burned by drilling machine during the drilling process. The pull-out was tested with different thickness grain direction with different dowel size with a rate of 2mm/min and the failure modes were observed after the testing of pull-out test. PRF is the adhesive used for the strengthening purposes. Resistance to the withdrawal of dowels glued-in perpendicularly was 44.2% to 53.5 % lower than that obtained for dowels glued-in parallel to the grain direction. The result shows that the dowel glued-in parallel to the grain given the higher maximum load than dowel glued-in perpendicular to the grain direction.

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