• Proceeding of KASS Symposium
• /
• 2008.05a
• /
• pp.70-73
• /
• 2008

Because the inclination and crack of stone pagoda structure are caused by the depth difference of soft soil ground and ground subsidence in weak zone, a long-term conservation of stone pagoda structure is difficult. But it is insufficient to analyze the behavior of stone pagoda structure considering soft soil ground in our country. Therefore, we find the structural effect happening in stone pagoda structure by analyzing mechanically a specific of soft soil ground and carry out structural analysis and structural modelling of stone pagoda structure that considers soft soil ground by discrete element method.

• Journal of the Korean GEO-environmental Society
• /
• v.6 no.1
• /
• pp.33-44
• /
• 2005

The 'Silt Pond' is 180 hectares in size and contained ultra soft slurry-like soil varying between 3 to 20 meters in thickness. Soil improvement work in the Silt Pond commenced by installing vertical drains in the mid of 1996, following completion of sand spreading up to +4.0m CD. Prior to soil improvement work in the main area of Silt Pond, experimental tests including laboratory tests with a large diameter consolidation cell and pilot tests were carried out to investigate the deformation behavior of an extremely soft soil. Due to its high compressibility, large strain usually occurred in the initial stage of deformation does not comply with Terzaghi's one dimensional consolidation theory. Taking into consideration experimental test results, the soil improvement works were carried out in main area of Silt Pond containing ultra soft soil. This paper presents the case study on improvement of ultra-soft soil.

• Earthquakes and Structures
• /
• v.24 no.5
• /
• pp.345-352
• /
• 2023

This paper studied the effect of soil-structure interaction (SSI) on the seismic response and retrofit of a reinforced concrete structure with a soft-first story for different soil types. A 5-story structure built on a 30m deep homogeneous soil mass was considered as a case study structure, and steel column jacketing and steel bracing were chosen as seismic retrofit methods. Seismic responses of a fixed-base and a flexible base structure subjected to seven scaled earthquake records were obtained using the software OpenSees to investigate the effect of soil on seismic response and retrofit. The nonlinearBeamColumn elements with the fiber sections were used to simulate the nonlinear behavior of the beams and columns. Soil properties were defined based on shear wave velocity according to categorized site classes defined in ASCE-7. The finite element model of the soil was made using isoparametric four-noded quadrilateral elements and the nonlinear dynamic responses of the combined system of soil and structure were calculated in the OpenSees. The analysis results indicate that the soil-structure interaction plays an important role in the seismic performance and retrofit of a structure with a soft-first story. It was observed that column steel jacketing was effective in the retrofit of the model structure on a fixed base, whereas stronger retrofit measures such as steel bracing were needed when soil-structure interaction was considered.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09b
• /
• pp.152-160
• /
• 2010

In this study, cohesion of soft ground, soft ground depth and embankment height varying conditions, such as the impact of each condition after the calculation of the range, SCP was performed to evaluate the applicability of the method. Reinforcing effects of scope, and permit lateral movement of SCP 2D and 3D analysis of the program were calculated by the displacement ratio, the result follows. The height and depth of soft soil embankment with increasing and decreasing the cohesion tends to be affected were long range, SCP method applied by the finite element analysis Cu = 1.0tf/$m^2$, embankment height is 3.0m depth of soft soil can be applied in a less than 5.0m, and Cu = 3.0tf/$m^2$, embankment height, the soft soil depth is 3.0m 12.0m, Cu = 3.0tf/$m^2$, embankment height is 5.0m less than 7.0m depth of soft soil can be applied in was. And Cu = 5.0tf/$m^2$, embankment height is 3.0m below 15.0m depth rouge anti Floor, Cu = 3.0tf/$m^2$, embankment height of 5.0m 12.0m depth below the soft soil, Cu = 5.0tf/$m^2$, If the depth of soft soil embankment height of 7.0m and below 5.0m was applicable.

• Journal of the Korean Geotechnical Society
• /
• v.32 no.6
• /
• pp.5-16
• /
• 2016

In the geosynthetics-reinforced piled embankment the effects of soft soil stiffness, friction angle of the fill material, tensile stiffness of geosynthetics, and height of the embankment on the load transfer soil arch measured by the critical height were numerically investigated. Results from parametric studies show that the magnitude of the soft soil stiffness is the most influencing factor on the critical height. The contour charts of the critical height with respect to the combination of the soft soil stiffness and other parameters were presented. The charts show that the critical height sensitively varies with the combination of the soft soil stiffness and the height of embankment. Under the sufficiently low stiffness of soft soil, the critical height sensitively varies with the friction angle of the fill material. Once the geosynthetic layer is placed, however, the magnitude of the tensile stiffness of the geosynthetic layer hardly influences the critical height of the soil arch.

• Earthquakes and Structures
• /
• v.3 no.3_4
• /
• pp.549-561
• /
• 2012

Many building foundations are embedded, however it is not easy to compact the backfill around the foundation especially for the deeply embedded ones. The soil condition around the embedded foundation may affect the seismic response of a building due to the weak contact between the soil and the foundation. In this paper, the response accelerations in the short-period range and at the period of 1 second (in the long-period range) for a seismic design spectrum specified in the IBC design code were compared considering perfect and poor backfills to investigate the effect of backfill compaction around the embedded foundation. An in-house finite-element software (P3DASS) which has the capability of horizontal pseudo-3D seismic analysis with linear soil layers was used to perform the seismic analyses of the structure-soil system with an embedded foundation. Seismic analyses were carried out with 7 bedrock earthquake records provided by the Pacific Earthquake Engineering Research Center (PEER), scaling the peak ground accelerations to 0.1 g. The results indicate that the poor backfill is not detrimental to the seismic response of a building, if the foundation is not embedded deeply in the soft soil. However, it is necessary to perform the seismic analysis for the structure-soil system embedded deeply in the soft soil to check the seismic resonance due to the soft soil layer beneath the foundation, and to compact the backfill as well as possible.

• Journal of the Korean Society of Safety
• /
• v.19 no.2
• /
• pp.119-124
• /
• 2004

The effect of soil-structure interaction becomes important in the design of civil structures such as long-span bridges, which are constructed in the site composed of soft soil. Many methodologies have been developed to account for the proper consideration of soil-structure interaction effect. However, it is difficult to estimate soil-structure interaction effect accurately becaused of many uncertainties. This paper presents the results of study on soil-structure interaction and dynamic response of a long-span bridge designed in the site composed of soft soil. The effect of the soft soil was evaluated by the use of computer program SASSI and a long-span bridge structure was modeled by finite elements. Dynamic response characteristics of a long-span bridge considering soil-structure interaction wereinvestigated.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.1065-1072
• /
• 2010

The excavation site in the new city of inchon songdo is distributed with soft reclaimed soil and marine deposit. So, the general ground anchor is not applied to this layer of soft ground as the earth retaining support system, because of settlement. And then, Jacket pack anchor which is newly developed in order to increasing the pullout resistance by certain grout bulb formation and expansion effect in soft ground is applied to this site instead of the general ground anchor. Though the maximum horizontal displacement shows about 30mm~100mm (The maximum horizontal displacement/excavation depth$\fallingdotseq$0.32~1.0%) according to excavation sequence, generally excavation work finished stably. Also, load cell after setting shows almost increasing trend with increasing horizontal displacement. It means that the settlement of Jacket pack anchor in soft ground is good. From the result of this case, we knew that Jacket pack anchor was able to use the earth retaining support system in soft ground. Using Jacket pack anchor in soft ground, The allowance of the horizontal displacement is applied more than general value considering soil factors.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2004.03b
• /
• pp.227-234
• /
• 2004

Sand compaction pile (SCP) method is composed of compacted sand pile inserted into the soft clay deposit by displacement method. SCP-reinforced ground is composite soil which consists of the SCP and the surrounding soft soil. When a surcharge load is applied on composite ground, time-dependent behavior occurs in the soft soil due to consolidation according to radial flow toward SCP and stress transfer also takes place between the SCP and the soft soil. This paper presents the numerical results of cylindrical composite ground that was conducted to investigate consolidation characteristics and the stress transfer mechanism of SCP-reinforced composite ground. The results show that the consolidation of soft clay has a significant effect on the stress transfer mechanism and stress concentration ratio of composite ground

• Journal of the Korean Society of Safety
• /
• v.20 no.1 s.69
• /
• pp.101-106
• /
• 2005

When a underground structure is constructed at the site composed of soft soil, the behavior of a underground structure Is much affected by the motion of soft soil. Therefore, the effect of soil-structure interaction is an important consideration in the design of a underground structure such as tunnel at the site composed of soft soil. This paper presents the results of the study on dynamic response of tunnel structures and soil-structure interaction effects. The computer program SASSI was used in seismic analysis of tunnel structures because it is more capable of analyzing dynamic response or structures considering soil-structure interaction. As regards the results, the flexibility of surrounding soil affects dynamic response characteristics of tunnel structures and response of tunnel structures can be amplified.