Three-dimensional Discrete Element Simulation of Interaction between Aqueduct and Tunnel

In this investigation the effect of interaction between aqueduct and tunnel on the ground settlement has been examined using PFC3D. At first, the calibration of PFC3D was conducted based on UCS test results rendered from three different ground layer. Then intact model with dimension of 70 m × 20 m × 34.5 m (x × y × z) was built. These models are consisted of 8 layers with different mechanical and geometrical properties. Four different configurations for aqueduct were created in four models. Diameter of aqueduct was 2 m and its depth was different in four models. After aqueduct generation, tunnel with diameter of 9 m and length of 20 m was drilled in depth of 22 m. After tunnel drilling, the settlement data of ground surface were picked up. After tunnel simulation, the effect of support lining was investigated on the ground settlement. For this purpose, after each step of tunnel drilling, lining support with diameter of 35 cm was performed. The results show that the maximum value of settlement occurred when aqueduct reach to head of tunnel. Also the safety has maximum value when the distance between aqueduct and tunnel wall was 4.5 m. the ground settlement before and after support lining shows that ground settlement reach to zero by support application.

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The Ground Settlement and the Existing Pipeline Response Induced by the Nonsynchronous Construction of a Twin-Tunnel

Advances in Civil Engineering ◽

10.1155/2021/8815304 ◽

2021 ◽

Vol 2021 ◽

pp. 1-12

Author(s):

Shicheng Sun ◽

Chuanxin Rong ◽

Houliang Wang ◽

Linzhao Cui ◽

Xin Shi

Keyword(s):

Three Dimensional ◽

Ground Surface ◽

Construction Process ◽

Ground Settlement ◽

Three Dimensional Model ◽

Relative Stiffness ◽

Twin Tunnel ◽

Calculation Results ◽

Negative Impacts ◽

Final Settlement

Shielding tunnel construction always has negative impacts on the surrounding buildings. Because of repeated disturbances caused by the construction, more attention should be paid to the impacts of the nonsynchronous construction of a twin-tunnel. In this research, a three-dimensional model was established to simulate the construction process of a twin-tunnel in a section of the Hefei No. 4 metro line, and the calculation results were validated with the measured settlement data. Based on the model, the ground settlement and the existing pipeline responses were studied in detail. The results showed that, after the first tunnel (FT) construction, the settlement curves conformed to a Gaussian distribution. Additionally, after the second tunnel (ST) construction, the final settlement curves were no longer completely symmetrical. The influences of the twin-tunnel space and the pipeline-soil relative stiffness on the settlements were further studied. The results showed that the final settlement curves of the ground surface and the pipeline were mainly W-shaped, U-shaped, and V-shaped. As the twin-tunnel space increased and the pipeline-soil relative stiffness decreased, the settlement curve gradually changed from V-shaped to W-shaped. C was defined as the ratio of two maximum settlements in the W-shaped settlement curve. As the space increased, C started to decrease from 1 and then increased to 1.

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Three Dimensional Numerical Analysis of Ground Settlement Induced by Shield Tunneling

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.182-183.937 ◽

2012 ◽

Vol 182-183 ◽

pp. 937-940

Author(s):

Zhong Chang Wang

Keyword(s):

Soil Layer ◽

Three Dimensional ◽

Ground Surface ◽

Vertical Displacement ◽

Ground Subsidence ◽

Shield Tunnel ◽

Ground Settlement ◽

Shield Tunneling ◽

Tunnel Face ◽

Maximum Settlement

The fine numerical simulation is used to study the ground settlement of complex stratum owing to shield construction by ANSYS program. It is shown that the closer the distance between soil layer and the axis of tunnel is, the smaller the disturbance of construction is, the obvious the ground surface settlement is. The value of the maximum settlement at the center of the surface is 7.4mm. The maximum settlement of vault is 14mm. The ground subsidence in cross section distribution is shaped of normal distribution. The closer the distance between soil layer and ground surface is, the smaller the vertical displacement is, the bigger the width of settlement trough of soil layers is. The width of settlement trough is 25m. The volume loss rate of shield tunnel is about 0.32%. The width coefficient of ground settlement trough is 0.56. The tendency of ground settlement decrease to become gentle with the advance of shield construction. The ground settlement keeps constant after tunnel face advancing to 30m.

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Effect of Pole Number on Generator End Winding Electromagnetic Force and Mechanical Response before and after RISC

International Journal of Rotating Machinery ◽

10.1155/2021/4375415 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

Hong-Chun Jiang ◽

Yu-Ling He ◽

Gui-Ji Tang

Keyword(s):

Electromagnetic Force ◽

Mechanical Response ◽

Short Circuit ◽

Three Dimensional ◽

Element Simulation ◽

Before And After ◽

Variation Characteristics ◽

Stress And Deformation ◽

Rotor Winding ◽

Similarity And Difference

This paper comparatively studies on the end winding electromagnetic force and mechanical response for generators with different numbers of poles. The analytical expression of the end winding electromagnetic force is derived under the rotor winding interturn short circuit (RISC) considering the pole number. Meanwhile, the three-dimensional transient finite element simulation is carried on two generators with one-pair poles and three-pair poles. Then, the frequency composition and amplitude variation characteristics of the radial, axial, and tangential electromagnetic forces are analyzed. Further, the maximum stress and deformation on the end winding are calculated and the similarity and difference of the coil failure law are obtained for two kinds of generators. It is found that RISC will bring odd harmonics to electromagnetic force for one-pair pole generators but it will bring odd and fraction harmonics for multipair pole generators. Moreover, the max mechanical response under RISC will decrease for one-pair pole generators but it will increase for multipair pole generators.

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Effect of Geometric Parameters and Construction Sequence on Ground Settlement of Offset Arrangement Twin Tunnels

Geosciences ◽

10.3390/geosciences12010041 ◽

2022 ◽

Vol 12 (1) ◽

pp. 41

Author(s):

Md Shariful Islam ◽

Magued Iskander

Keyword(s):

Three Dimensional ◽

Ground Surface ◽

Geometric Parameters ◽

Horizontal Distance ◽

Ground Settlement ◽

Construction Sequence ◽

Settlement Behavior ◽

Total Settlement ◽

Three Dimensional Finite Element ◽

Twin Tunnels

A parametric study that examines the ground surface settlement due to the excavation of shallow offset arrangement twin tunnels is presented. Offset arrangement tunnels are those that run parallel to each other, but at different elevations. The study focuses on the influence of both the construction sequence and various geometric parameters on the induced soil settlement. A series of three-dimensional finite element analyses was carried out to investigate the settlement behavior and interactions between offset arrangement twin tunnels excavated in clay using a simplified mechanized excavation method. Analyses were carried out for three cover-to-diameter (C/D) ratios, three possible construction sequences, five angular relative positions, and five angular spacings. In addition, settlement data were also investigated by varying horizontal and vertical spacings while keeping the angular spacing constant. The total settlement of the excavated twin tunnels and the settlement induced solely by the new second tunnel are both presented, and special attention was paid to identifying the dominant geometric parameters. The observed data trends from this study are generally consistent with the limited data available in the literature. This study confirmed a few perceived behaviors. First, angular relative position better describes the settlement behavior in comparison to angular spacing. Second, the effect of the vertical distance is noticeably more significant than that of the horizontal distance between the two tunnels. Third, excavation of the lower tunnel at first induces higher total ground settlement than when the upper tunnel is excavated first or when both tunnels are excavated concurrently. Fourth, settlement due to the construction of the newer tunnel decreases with the increase in the cover depth. In addition, two design charts have been proposed to calculate the settlement induced from a new second tunnel excavation and the eccentricity of the maximum total settlement relative to the center of the new tunnel.

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Three dimensional and Doppler ultrasound examination before and after procedures of the biliary system

Zeitschrift für Gastroenterologie ◽

10.1055/s-2008-1079705 ◽

2008 ◽

Vol 46 (05) ◽

Author(s):

G Székely ◽

Á Szilvás ◽

F Siket

Keyword(s):

Doppler Ultrasound ◽

Ultrasound Examination ◽

Three Dimensional ◽

Biliary System ◽

Before And After

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Redrawing Operation a Star Shape from Cylindrical Shape Using Experimental and FE Analysis

Engineering and Technology Journal ◽

10.30684/etj.v38i1a.191 ◽

2020 ◽

Vol 38 (1A) ◽

pp. 25-32

Author(s):

Waleed Kh. Jawad ◽

Ali T. Ikal

Keyword(s):

Finite Element ◽

Effective Strain ◽

Element Model ◽

Cylindrical Shape ◽

Element Analysis ◽

Punch Force ◽

Maximum Value ◽

Element Simulation ◽

Blank Sheet ◽

The Finite Element Model

The aim of this paper is to design and fabricate a star die and a cylindrical die to produce a star shape by redrawing the cylindrical shape and comparing it to the conventional method of producing a star cup drawn from the circular blank sheet using experimental (EXP) and finite element simulation (FES). The redrawing and drawing process was done to produce a star cup with the dimension of (41.5 × 34.69mm), and (30 mm). The finite element model is performed via mechanical APDL ANSYS18.0 to modulate the redrawing and drawing operation. The results of finite element analysis were compared with the experimental results and it is found that the maximum punch force (39.12KN) recorded with the production of a star shape drawn from the circular blank sheet when comparing the punch force (32.33 KN) recorded when redrawing the cylindrical shape into a star shape. This is due to the exposure of the cup produced drawn from the blank to the highest tensile stress. The highest value of the effective stress (709MPa) and effective strain (0.751) recorded with the star shape drawn from a circular blank sheet. The maximum value of lamination (8.707%) is recorded at the cup curling (the concave area) with the first method compared to the maximum value of lamination (5.822%) recorded at the cup curling (the concave area) with the second method because of this exposure to the highest concentration of stresses. The best distribution of thickness, strains, and stresses when producing a star shape by

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Finite element simulation of three dimensional residual stress in the aortic wall using an anisotropic tissue growth model

Journal of the Mechanical Behavior of Biomedical Materials ◽

10.1016/j.jmbbm.2019.01.007 ◽

2019 ◽

Vol 92 ◽

pp. 188-196 ◽

Cited By ~ 5

Author(s):

Haofei Liu ◽

Ming Zhang ◽

Minliang Liu ◽

Caitlin Martin ◽

Zongxi Cai ◽

...

Keyword(s):

Residual Stress ◽

Finite Element ◽

Finite Element Simulation ◽

Growth Model ◽

Aortic Wall ◽

Three Dimensional ◽

Tissue Growth ◽

Element Simulation

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Three-dimensional analysis of the root canal preparation with Reciproc Blue®, WaveOne Gold® and XP EndoShaper®: a new method in vivo

BMC Oral Health ◽

10.1186/s12903-021-01450-1 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Javier Caviedes-Bucheli ◽

Nestor Rios-Osorio ◽

Diana Usme ◽

Cristian Jimenez ◽

Adriana Pinzon ◽

...

Keyword(s):

3D Reconstruction ◽

Root Canal ◽

Paired Comparison ◽

Three Dimensional ◽

New Method ◽

Root Canal Preparation ◽

Paired Data ◽

Before And After ◽

Student’S T

Abstract Background The purpose of this study was to evaluate the changes in canal volume after root canal preparation in vivo with 3 different single-file techniques (Reciproc-Blue®, WaveOne-Gold® and XP-EndoShaper®), with a new method using CBCT and 3D reconstruction. Methods In this prospective study, thirty human lower premolars from healthy patients were used, in which extraction was indicated for orthodontic reasons. All the teeth used were caries- and restoration-free with complete root development, without signs of periodontal disease or traumatic occlusion, and with only one straight canal (up to 25º curvature). Teeth were randomly divided into three different groups: Reciproc-Blue, WaveOne-Gold and XP-EndoShaper. CBCT scans before root canal preparation were used to create a 3D reconstruction with RHINOCEROS 5.0 software to assess the initial canal volume, and then compared with 3D reconstructions after canal preparation to measure the increase in canal volume. Student’s t test for paired data were used to determine statistically significant differences between the before and after canal volumes. Anova test was used to determine statistically significant differences in the percentage of canal volume increase between the groups and Tukey's post-hoc test were used to paired comparison. Results Reciproc-Blue showed the higher increase in canal volume, followed by WaveOne-Gold and XP-EndoShaper (p = 0.003). XP-EndoShaper did not show a statistically significant increase in canal volume after root canal preparation (p = 0.06). Conclusion With this model, Reciproc-Blue showed higher increase in root canal volume, followed by WaveOne-Gold, while XP-EndoShaper did not significantly increase root canal volume during preparation.

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Scientific validation of three-dimensional stereophotogrammetry compared to the IGAIS clinical scale for assessing wrinkles and scars after laser treatment

Scientific Reports ◽

10.1038/s41598-021-91922-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Barbara Helena Barcaro Machado ◽

Ivy Dantas De Melo E. Silva ◽

Walter Marou Pautrat ◽

James Frame ◽

Mohammad Najlah

Keyword(s):

Laser Treatment ◽

Three Dimensional ◽

Skin Surface ◽

Clinical Scale ◽

3D Images ◽

Laser Resurfacing ◽

Before And After ◽

Measuring Outcomes ◽

Skin Scar ◽

Scientific Validation

AbstractMeasuring outcomes from treatments to the skin is either reliant upon patient’s subjective feedback or scale-based peer assessments. Three-Dimensional stereophotogrammetry intend to accurately quantify skin microtopography before and after treatments. The objective of this study is comparing the accuracy of stereophotogrammetry with a scale-based peer evaluation in assessing topographical changes to skin surface following laser treatment. A 3D stereophotogrammetry system photographed skin surface of 48 patients with facial wrinkles or scars before and three months after laser resurfacing, followed immediately by topical application of vitamin C. The software measured changes in skin roughness, wrinkle depth and scar volume. Images were presented to three observers, each independently scoring cutaneous improvement according to Investigator Global Aesthetic Improvement Scale (IGAIS). As for the results, a trend reflecting skin/scar improvement was reported by 3D SPM measurements and raters. The percentage of topographical change given by the raters matched 3D SPM findings. Agreement was highest when observers analysed 3D images. However, observers overestimated skin improvement in a nontreatment control whilst 3D SPM was precise in detecting absence of intervention. This study confirmed a direct correlation between the IGAIS clinical scale and 3D SPM and confirmed the efficacy and accuracy of the latter when assessing cutaneous microtopography alterations as a response to laser treatment.

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