• Tunnel and Underground Space
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• v.20 no.5
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• pp.352-359
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• 2010

Stability of twin tunnels depends on the pillar width and the ground condition. In this study, large scale model tests were conducted for investigating the influence of the pillar width of twin tunnels on their behavior in the regular horizontal jointed rock mass. Jointed rocks was composed of concrete blocks. Pillar width of twin tunnels varied in 0.29D, 0.59D, 0.88D and 1.18D, where D is the tunnel width. During the test, pillar stress, lining stress, tunnel distortion, and ground displacement were measured. Lateral earth pressure coefficient was kept in a constant value 1.0. As a result, it was found that the pillar stress and the displacement of the ground and tunnel were increased by decreasing pillar width. The maximum displacement rate was measured just after the upper excavation in each construction sequence. And the maximum influence position was the right shoulder of the preceeding tunnel at the pillar side. It was also found that for the stability assessment the inner displacement was more critical than the crown displacement. The influence zone was formed at the pillar width 0.59D~0.88D that was smaller than 0.8D~2.0D, which was proposed by experience for a good ground condition. And it would be concluded that horizontal joints could also influence on the stability of the twin tunnels.

• Journal of the Korean Geotechnical Society
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• v.15 no.4
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• pp.99-112
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• 1999

When there exists a fault zone ahead of the tunnel face and a tunnel is excavated without perceiving its existence, it will cause stress concentration in the region between the tunnel face and the fault zone because of the influence of the fault zone on the arching phenomena. Because the underground structure has many unreliable factors in the design stage, the prediction of a fault zone ahead of the tunnel face by monitoring plans during tunnel construction and the rapid establishment of appropriate support system are required for more economical and safer tunnel construction. Recent study shows that longitudinal displacement changes during excavation due to the change of rock property, and if longitudinal displacement and settlement, which are measured in the field, are considered together in displacement analysis, the prediction of change in rock mass property is possible. This study provided the method for the prediction of fault zones by analyzing the changes of L/C and (Ll-Lr)/C ratio (L= longitudinal displacement at crown, C = settlement at crown, Ll = longitudinal displacement at left sidewall, Lr = longitudinal displacement at right sidewall) and the stereographic projection of displacement vectors which were obtained from the 3-D numerical analysis of hybrid method in various initial stress conditions.

• Journal of the Korean GEO-environmental Society
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• v.7 no.4
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• pp.53-62
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• 2006

Recently, the lateral displacement of the passive piles which are installed under the revetment on the soft ground is very important during the land reclamation work along the coastal line. The revetment on the soft clay develops the lateral displacement of ground when the revetment loading exceeds a certain limit. The lateral displacement of ground causes an excessive deformation of underground structure itself and develops lateral earth pressure against the pile foundation. The subject of study is to investigate the lateral displacement of pile foundation during the construction of container terminal at the ${\bigcirc}{\bigcirc}{\bigcirc}{\bigcirc}$ port in Incheon. The displacement of pile and the vertical settlement were measured in the field and finite element method(FEM) analysis for each construction sequence was performed using AFFIMEX(Ver 3.4). From the comparison of the results from field measurement and the finite element analysis, the settlement of the reventment has already occurred at the time of field measurements. Since then, the noticeable lateral displacement of piles and settlement were occurred during the filling of dredged soil inside the revetment dredging and reclaiming work. After completing filling, the lateral displacement and field settlement were reduced remarkably. Generally, the results from the finite element analysis show larger than those from the measurement.

• Clinics in Shoulder and Elbow
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• v.2 no.1
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• pp.28-34
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• 1999

Purpose: We studied magnetic resonance imaging of acromion morphology and superior displacement of the humeral head in the patients with diagnosis of rotator cuff impingement syndrome, and also documented the relationship of type Ⅲ acromion to the rotator cuff tear. Materials and Methods: We reviewed retrospectively 40 patients(40 shoulders) who had arthroscopic treatment for the diagnosis of stage II impingement or rotator cuff partial tear and did not have other risk lesions except acromion factor. The mean age was 48.7 years at operation. 21 men(2l shoulders), mean age of 26 years, were used as controls. Acromial type, tilt, and superior displacement of humeral head in sagittal plane, and acromial lateral angulation in coronal plane were measured. Four parameters of the patients were compared with those of control group. And then, the data were subdivided and analyzed with respect to acromial type and patient age in the impingement group. Student t test and multi-way ANOVA were used. Results: In impingement group, Farley's type I acromion, 33%, type Ⅱ, 38%, type Ⅲ, 27% and type Ⅳ, 2%. Superior displacement of humeral head( 4.8mm) were characteristic in the impingement group compared with the control group(1.3mm)(p<0.05). But acromial tilt and lateral angulation were not statistically different. In the analysis of the impingement group, the change of 4 parameters was not significant with respect to age(p>0.05), but lateral angulation in type I acromion(18 degree) and superior displacement of humeral head in type Ⅲ acromion(6.3mm) were significantly increased(p<0.05). All 4 parameters were not different between two subdivided types of type Ⅲ acromion. Conclusion: All types of acromian and large lateral angulatian cauld develop impingement syndrame, but acromial tilt was nat risk factar. Appearance of type Ⅲ acromian and increased superiar displacement of humeral head were characteristic findings in the impingement syndrame. Superiar displacement of humeral head as a result of degenerative change of rotatar cuff was probably primary cause far impingement. The type Ⅲ acromian might be an acquired farm, which cauld be expected to accelerate the tear of rotatar cuff as a cansequence.

• The korean journal of orthodontics
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• v.41 no.4
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• pp.237-254
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• 2011

Objective: The purpose of this study was to compare the displacement patterns shown by finite element analysis when the maxillary anterior segment was retracted from different orthodontic miniscrew positions and different lengths of lever arms in lingual continuous and segmented arch techniques. Methods: A three dimensional model was produced, the translation of teeth in both models was measured and individual displacement was calculated. Results: When traction was carried out from miniscrews in the palatal slope, lingual tipping of crowns and extrusion of the maxillary anterior segment were found in both continuous and segmented arches as the lever arms were made shorter. With miniscrews in the midpalatal suture area, the displacement patterns were similar to the palatal slope, but bodily movement of the upper incisors was observed in both continuous and segmented arches with the lever arm at 20 mm. When lever arms were longer, there was less extrusion of the incisors and more buccal displacement of the canines. Such displacement was shown less in the continuous arch than the segmented arch. The second premolar showed crown mesial tipping and intrusion, and the molars showed distal tipping in the continuous arch. The posterior segment was displaced three dimensionally in the segmented arch, but the amount of displacement was less than the continuous arch. Conclusions: It is recommended that lever arms of 20 mm in length be used for bodily movement of the anterior segment. Use of continuous or segmented arches affect the displacement patterns and induce differences in the amount of displacement.

• Geotechnical Engineering
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• v.9 no.1
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• pp.59-68
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• 1993

In deep excavations for creation of underground spaces, it would be difficult to predict earth pressure, especially multilayered ground including rock strata. The earth pressures and displacements on the retention walls are measured by load cell, strain gauge and inclinometer which were installed at struts or anchors at 4 deep excavation sites in Seoul area. In this paper, the measured earth pressure from the struts or anchors are compared with Peck's empirical values, and the coefficient of the earth pressures for each strata and horizontal wall displacement are investigated. The coefficient of earth pressure distribution, a(0.65zka), in the flexible and the rigid walls was about 74% and 88% of Peck's value respecitively. The measured earth pressure distributions for the 4 sites showed about 70%∼80% of Peck's empirical values and the average earth pressure coefficients based on the measured data were 0.3 for the felted layer, 0.23 for the weathered rock and 0.19 for the weak rock. The maximum w리1 displacements were found to be less 0.2% of excavation depth.

• Transactions of Materials Processing
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• v.26 no.1
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• pp.41-47
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• 2017

Cyclic behavior of advanced high strength steel sheets was measured using an inverse-optimization approach with pre-straining and bending. First, tensile specimens were pre-strained, and three-point bending was conducted for the pre-strained specimens. By using the inverse finite element optimization, the combined isotropic-kinematic hardening parameters that minimize the error between the measured and predicted bending force-displacement curves. The measured cyclic behavior agreed well with the cyclic behavior measured by sheet tension-compression test, which confirms the validity of the measuring procedure based on inverse optimization.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.253-259
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• 2002

The rigid body characteristics (value of mass, Position of center of mass, moments and products of inertia) of mechanical systems can be identified from FRF data or vibration spectra of rigid body motion. Therefore the accuracy of rigid body characteristics is connected directly with the accuracy of measured data for rigid body motions. In this paper, a method of improving accuracy of measurement of rigid body motion is presented. Applying rigid body theory, ail translational and rotational displacements at a tentative point on the rigid body are calculated using the measured translational displacements for several points and transfer matrix. Then the estimated displacements for the identical points are calculated using the 6 displacements of the tentative Point and transfer matrix. By using correlation coefficient between measured and estimated displacements, we can detect the existence of errors that are contained in a certain measured displacement. Consequently, the improved rigid body motion with respect to a tentative point can be obtained by eliminating the contaminated data.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1999.03a
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• pp.147-152
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• 1999

We have measured viscoelastic properties of fabrics in thickness direction. We assume that Maxwell model is very useful in stress relaxation of viscoelastic theories and appropriate formulas for fabric are calculated. Measurement system constitute of high precession load cell, translator and laser displacement sensor for viscoelastic properties was designed and elastic coefficients and damping coefficients were measured for 10 fabric samples. Elastic coefficients measured were 19~25 kN/㎡ and Damping coefficients measured were 4.8~8.7 MN$.$s/㎡. We concluded that these coefficients are good related with FUKURAMI collected from KESF system

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.186-188
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• 1994

Fundamental characteristics of Giant Magnetostrictive Alloy Terfenol-D$(Tb_{0.3}Dy_{0.7}Fe_{1.9\sim1.95})$ were measured by experiments. Magnetostrictions of Terfenol-D samples whose lengths are 15 and 25 mm have been measured under compressive stress from 0 to 14 MPa, when the applied magnetic field was up to 1200 Oe. The relationship between magnetostriction and field is shown graphically in the form of $H-{\lambda}$, curve. For the experiment, solenoid magnet and lever-arm-type stress equipment were designed and fabricated. The magnetostriction is measured by laser displacement measuring system and the stress applied to the sample is measured by load cell.