• Journal of the Korean Geosynthetics Society
• /
• v.16 no.4
• /
• pp.43-55
• /
• 2017

The purpose of this study is to investigate the effect of traffic loads on retaining wall stability. There is insufficient research on lateral earth pressure on retaining wall due to traffic load. In addition, limited detailed designs of retaining wall for transportation including number of lanes of road, magnitudes of axle loads, and vehicle formations are available. Because the lateral earth pressure on the retaining wall due to traffic loads is a function of the lateral distance from retaining wall, the wall height, and the locations of lanes, the analysis of lateral load on retaining wall from traffic loads is performed with direct or indirect reflection of these factors. As a result of the analysis, lateral earth loads induced from traffics can be considered negligible if the lateral distance of traffic load from wall exceeds the height of retaining wall. Therefore, it is practically reasonable to consider traffic loads within a lateral distance between wall and traffic load of the height of retaining wall.

• Journal of the Korean Geotechnical Society
• /
• v.23 no.5
• /
• pp.77-88
• /
• 2007

Lateral earth pressure and horizontal displacement of the diaphragm walls constructed in multi-soil layers were analyzed by the field instrumentation from six building construction sites in urban area. The distribution of the developed earth pressure of the anchored diaphragm walls during excavation shows approximately a trapezoid diagram. The maximum earth pressure of anchored diaphragm walls corresponds to $0.45{\gamma}H$ and the earth pressure acts at the upper part of the walls. The maximum earth pressure is two times larger than the empirical earth pressure of flexible walls in sands suggested by Terzaghi and Peck(1967), Tschebotarioff(1973), and Hong and Yun(1995a). The horizontal displacement of diaphragm walls is closely related with supporting systems such as struts, anchors, and so on. The horizontal displacement of anchored walls shows less than 0.1 percent of the excavated depth, and the horizontal displacement of strutted walls shows less than 0.25 percent of the excavated depth. Therefore, the restraining effect of horizontal displacement to the anchored diaphragm walls is larger than the strutted diaphragm walls. In addition, since the horizontal displacement of the diaphragm walls is lower than the criterion, $\delta=0.25%H$, used for control the anchored retention wall using soilder piles, the safety of excavation sites applied with the diaphragm walls is pretty excellent.

• Geotechnical Engineering
• /
• v.14 no.4
• /
• pp.177-204
• /
• 1998

In the present study, a method of quasi-three dimensional stability analysis is proposed for a systematic design of the GRS-RW(Geosynthetic-Reinforced Soil Retaining Wall) system based on the postulated three dimensional failure wedge. The proposed method could be applied to the analysis of the stability of both the straight-line and cove-shaped are. As with skew reinforcements. Maximum earth thrust expected to act on the rigid face wall is assumed to distribute along the depth, and wall displacements are predicted based on both the assumed compaction-induced earth pressures and one dimensional finite element method of analysis. For a verification of the procedure proposed in the present study, the predicted wall displacements are compared with chose obtained from the RMC tests in Canada and the FHWA tests in U.S.A. In these comparisons the wall displacements estimated by the methods of Christopher et at. and Chew & Mitchell are also included for further verification. Also, the predicted wall displacements for the convex-shaped zone reinforced with skew reinforcements are compared with those by $FLAC_{3D}$ program analyses. The assumed compaction-induced earth pressures evaluated on the basic of the proposed method of analysis are further compared with the measurements by the FHWA best wall. A parametric stduy is finally performed to investigate the effects of various design parameters for the stability of the GRS-RW system

• Geophysics and Geophysical Exploration
• /
• v.11 no.1
• /
• pp.41-51
• /
• 2008

To construct in situ velocity-porosity relationships for oceanic basalt, considering crack features, P- and S-wave velocity measurements on basaltic samples obtained from the eastern flank of the Juan de Fuca Ridge were carried out under confining pressures up to 40 MPa. Assuming that the changes in velocities with confining pressures are originated by micro-crack closure, we estimated micro-crack aspect ratio spectra using the Kuster-$Toks{\ddot{o}}z$ theory. The result demonstrates that the normalised aspect ratio spectra of the different samples have similar characteristics. From the normalised aspect ratio spectrum, we then constructed theoretical velocity-porosity relationships by calculating an aspect ratio spectrum for each porosity. In addition, by considering micro-crack closure due to confining pressure, a velocity-porosity relationship as a function of confining pressure could be obtained. The theoretical relationships that take into account the aspect ratio spectra are consistent with the observed relationships for over 100 discrete samples measured at atmospheric pressure, and the commonly observed pressure dependent relationships for a wide porosity range. The agreement between the laboratory-derived data and theoretically estimated values demonstrates that the velocity-porosity relationships of the basaltic samples obtained from the eastern flank of the Juan de Fuca Ridge, and their pressure dependence, can be described by the crack features (i.e. normalised aspect ratio spectra) and crack closure.

• International Journal of Highway Engineering
• /
• v.3 no.4 s.10
• /
• pp.127-136
• /
• 2001

To increase the structural integrity of concrete box culvert good compaction by the dynamic compaction roller with bi9 capacity is as effective as good backfill materials. It is needed for effective compaction that a compaction roller closes to concrete structure with high frequency. However structural distress of the culvert could be occur due to the excessive earth pressure by great dynamic compaction load. To investigate the characteristics of Induced stress by compaction, a box culvert was constructed with changing cushion materials and compaction methods. Two types of cushion material such as tire rubber chip and EPS(Expanded Polystyrene) were used as cushion panels and they are set on the culverts before backfill construction. Laboratory test result of cushion material says that the value of dynamic elastic modulus of rubber is lesser than that of EPS. On the other hand, material damping of rubber material is greater than that of EPS. In most case, dynamic compaction rollers with 10.5 ton weights were used and vibration frequency was applied 30Hz for the great compaction energy. This paper presents the main results on the characteristics of dynamic earth pressures during compaction. The amounts of induced dynamic pressures$(\Delta\sigma\;h)$ by compaction are affected with construction condition such as compaction frequency, depth of pressure cell, distance between roller and the wall of culvert and roller direction. Based on the measured values dynamic lateral pressure on the culverts, it could be said that orthogonal direction of roller to the length of culvert is more effective to compaction efficiency than parallel direction.

• Geophysics and Geophysical Exploration
• /
• v.9 no.1
• /
• pp.60-66
• /
• 2006

Three differing sandstones, two synthetic and one field sample, have been tested ultrasonically under a range of confining pressures and pore pressures representative of in-situ reservoir pressures. These sandstones include: a synthetic sandstone with calcite intergranular cement produced using the CSIRO Calcite In-situ Precipitation Process (CIPS); a synthetic sandstone with silica intergranular cement; and a core sample from the Otway Basin Waarre Formation, Boggy Creek 1 well, from the target lithology for a trial $CO_2$ pilot project. Initial testing was carried on the cores at "room-dried" conditions, with confining pressures up to 65 MPa in steps of 5 MPa. All cores were then flooded with $CO_2$, initially in the gas phase at 6 MPa, $22^{\circ}C$, then with liquid-phase $CO_2$ at a temperature of $22^{\circ}C$ and pressures from 7 MPa to 17 MPa in steps of 5 MPa. Confining pressures varied from 10 MPa to 65 MPa. Ultrasonic waveforms for both P- and S-waves were recorded at each effective pressure increment. Velocity versus effective pressure responses were calculated from the experimental data for both P- and S-waves. Attenuations $(1/Q_p)$ were calculated from the waveform data using spectral ratio methods. Theoretical calculations of velocity as a function of effective pressure for each sandstone were made using the $CO_2$ pressure-density and $CO_2$ bulk modulus-pressure phase diagrams and Gassmann effective medium theory. Flooding the cores with gaseous phase $CO_2$ produced negligible change in velocity-effective stress relationships compared to the dry state (air saturated). Flooding with liquid-phase $CO_2$ at various pore pressures lowered velocities by approximately 8% on average compared to the air-saturated state. Attenuations increased with liquid-phase $CO_2$ flooding compared to the air-saturated case. Experimental data agreed with the Gassmann calculations at high effective pressures. The "critical" effective pressure, at which agreement with theory occurred, varied with sandstone type. Discrepancies are thought to be due to differing micro-crack populations in the microstructure of each sandstone type. The agreement with theory at high effective pressures is significant and gives some confidence in predicting seismic behaviour under field conditions when $CO_2$ is injected.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.03a
• /
• pp.932-939
• /
• 2005

Recently, the lateral displacement of the passive piles which installed under the revetment on 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 the ground when the revetment loading is exceeded a certain limit. The lateral displacement of ground causes an excessive deformation of under structure itself and develops lateral earth pressure against the pile foundation as well. Especially passive piles subjected to lateral earth pressures are likely to have excessive horizontal displacement and large bending moment, which induces structural failure of pile foundation and harmful effects on superstructure. The subject of study is to investigate the later displacement of pile foundation during the construction of container terminal at the south port of Incheon. Actual field measurement data and finite element method(FEM) by AFFIMEX Ver 3.4 were used to analyze the displacement of pile and the vertical settlement of soft ground. This analysis was carried out at each sequence of construction work.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.03a
• /
• pp.1546-1553
• /
• 2005

In this study, geotextiles was applied on the selected track-bed, which is relatively economical and efficient way to prevent the problem of mud-pumping and settlement. Field testing sections from Mock-haeng to Dong-ryang in the Chung-buk lines in Korea were selected to investigate the state of track and roadbed. And three places were chosen among 1,700 spots where mud-pumping was frequently occurred and maintenance required. At the curved section with radius of 500m between Mock-haeng and Dong-ryang, we divided this testing site into 5 section and 4 different types of geotextile were installed and left the last section with no reinforcement. Total length of the test site was 200m and individual length of each site was 40 m. In order to understand the state and the strength of prepared roadbed, stiffness and physical properties of the roadbed soil were evaluated and analyzed. Also, after the installation, mud-pumping, settlement of elastic or plastic sleeper, failure of track, wheel-loads, lateral force and earth pressures were investigated.

• Proceedings of the KSR Conference
• /
• 2005.05a
• /
• pp.734-743
• /
• 2005

In this study, geotextiles was applied on the selected track-bed, which is relatively economical and efficient way to prevent the problem of mud-pumping and settlement. Field testing sections from Mock-haeng to Dong-ryang in the Chung-La lines in Korea were selected to investigate the state of track and roadbed. And three places were chosen among 1,700 spots where mud-pumping was frequently occurred and maintenance required. At the curved section with radius of 500m between Mock-haeng and Dong-ryang, we divided this testing site into 5 section and 4 different types of geotextile were installed and left the last section with no reinforcement. Total length of the test site was 200m and individual length of each site was 40 m. In order to understand the state and the strength of prepared roadbed, stiffness and physical properties of the roadbed soil were evaluated and analyzed. Also, after the installation, mud-pumping, settlement of elastic or plastic sleeper, failure of track, wheel-loads, lateral force and earth pressures were investigated.

• Geomechanics and Engineering
• /
• v.7 no.3
• /
• pp.263-277
• /
• 2014

In the conventional design of retaining structures in a seismic zone, seismic inertia forces are commonly assumed to act upwards and towards the wall facing to cause a maximum active thrust or act upwards and towards the backfill to cause a minimum passive resistance. However, under certain circumstances this design approach might underestimate the dynamic active thrust or overestimate the dynamic passive resistance acting on a rigid retaining structure. In this study, a new analytical method for dynamic active and passive forces in c-${\phi}$ soils with an infinite slope was proposed based on the Rankine earth pressure theory and the Mohr-Coulomb yield criterion, to investigate the influence of seismic inertia force directions on the total active and passive forces. Four combinations of seismic acceleration with both vertical (upwards or downwards) and horizontal (towards the wall or backfill) directions, were considered. A series of dimensionless dynamic active and passive force charts were developed to evaluate the key influence factors, such as backfill inclination ${\beta}$, dimensionless cohesion $c/{\gamma}H$, friction angle ${\phi}$, horizontal and vertical seismic coefficients, $k _h$ and $k_v$. A comparative study shows that a combination of downward and towards-the-wall seismic inertia forces causes a maximum active thrust while a combination of upward and towards-the-wall seismic inertia forces causes a minimum passive resistance. This finding is recommended for use in the design of retaining structures in a seismic zone.