• Title/Summary/Keyword: 지반지지력

Search Result 934, Processing Time 0.03 seconds

Experimental Study on the End Bearing Capacity of the Pile in a Group Pile (무리말뚝을 구성하는 개별말뚝의 선단지지력에 대한 실험연구)

  • Na, Yong Soo;Lee, Sang Duk
    • Journal of the Korean Geotechnical Society
    • /
    • v.35 no.6
    • /
    • pp.27-38
    • /
    • 2019
  • Bearing capacity of a pile in homogeneous soil is the sum of end bearing and skin resistance, and the skin resistance is more prominent in sandy soil. Bearing capacity of a pile in pile groups especially in sandy ground should be designed under the consideration of the influence by the adjacent piles. In this study, the end bearing capacity of a pile in pile groups was experimentally investigated. For this purpose, piles were installed in sandy ground in a circular test box, and end bearing - settlement behavior of the pile was measured while the pile was loaded. As the results, end bearing - settlement relation curves of the piles showed a distinct limit value. Limit value of the end bearing was little affected by skin friction and pile diameter, and it became a constant value as pile penetrates deeper. End bearing was not affected by the adjacent piles in a group of piles, when their clearance was larger than the pile diameter.

A Study on Behaviour of Sandy Ground Reinforced by Geotextiles with Equal Vertical Spacings (일정한 연직간격의 지오텍스타일로 보강된 모래지반의 거동에 관한 연구)

  • Joo, In-Gon;Park, Yong-Boo;Park, Jong-Bae
    • Land and Housing Review
    • /
    • v.2 no.1
    • /
    • pp.79-85
    • /
    • 2011
  • The bearing capacity of a soil can be improved by conventional ground improvement techniques such as stabilization and compaction methods. Recently, the use of geotextiles in improving the bearing capacity of soils has become popular because of the availability of durable and strong geosynthetic materials. In this paper, through the laboratory model tests on sandy ground reinforced by geotextiles with the strip footing under plane strain condition, the effects of bearing capacity improvement on the sandy ground and its behaviour were investigated.

Comparison of Bearing Capacity between SCP and GCP by Unit Cell Model Tests (단일말뚝 형태의 모형시험을 통한 SCP와 GCP의 극한지지력 비교)

  • 김병일;이승원;김범상;유완규
    • Journal of the Korean Geotechnical Society
    • /
    • v.20 no.8
    • /
    • pp.41-48
    • /
    • 2004
  • Several centrifuge modelling tests were performed to compare sand compaction pile (SCP) with gravel compaction pile (GCP) at the point of bearing capacity. SCP and GCP were installed as 30, 40, 50, 60, 70% of replacement ratio in cylindrical model tank (diameter = 20 cm, height = 40 cm), and the loading tests were carried out to analyze the bearing characteristics of soft clay ground reinforced by SCP and GCP. As a result of loading tests, the bearing capacities of soft grounds reinforced by SCP and GCP increase with increasing replacement ratio of pile, and a GCP reinforced ground has larger bearing capacity than that of a SCP reinforced ground. Several proposed bearing capacity equations for ground reinforced by SCP or GCP were compared with loading test results.

Characteristics of Bearing Capacity and Settlement According to the Difference of Loading Plate Sizes (재하판의 크기에 따른 지지력 및 침하특성)

  • 정형식;김도열
    • Journal of the Korean Geotechnical Society
    • /
    • v.18 no.4
    • /
    • pp.179-188
    • /
    • 2002
  • The scale effect should be considered to determine the bearing capacity and settlement of footings from plate-load test, because of the size difference between a footing and a loading plate. To analyze characteristics of bearing capacity and settlement according to the difference of loading plate sizes, model tests were performed with four different sizes of square plate, which are B=10, 15, 20, and 25cm respectively, on five different kinds of subsoils. Test results showed that the ultimate bearing capacity of a footing on the sand did not increase proportional to the traditional formula and the bearing capacity on the clay also increased a little with increasing the size of loading plate. The settlement of test plate on the sand did not increase as the traditional formula of Terzaghi and Peck (1967), and the settlement on the clay also did not increase proportional to the traditional formula.

Prediction of Ultimate Bearing Capacity of Soft Soils Reinforced by Gravel Compaction Pile Using Multiple Regression Analysis and Artificial Neural Network (다중회귀분석 및 인공신경망을 이용한 자갈다짐말뚝 개량지반의 극한 지지력 예측)

  • Bong, Tae-Ho;Kim, Byoung-Il
    • Journal of the Korean Geotechnical Society
    • /
    • v.33 no.6
    • /
    • pp.27-36
    • /
    • 2017
  • Gravel compaction pile method has been widely used to improve the soft ground on the land or sea as one of the soft ground improvement technique. The ultimate bearing capacity of the ground reinforced by gravel compaction piles is affected by the soil strength, the replacement ratio of pile, construction conditions, and so on, and various prediction equations have been proposed to predict this. However, the prediction of the ultimate bearing capacity using the existing models has a very large error and variation, and it is not suitable for practical design. In this study, multiple regression analysis was performed using field loading test results to predict the ultimate bearing capacity of ground reinforced by gravel compaction pile, and the most efficient input variables are selected through evaluation of error by leave one out cross validation, and a multiple regression equation for the prediction of ultimate bearing capacity was proposed. In addition, the prediction error was evaluated by applying artificial neural network using the selected input variables, and the results were compared with those of the existing model.

A Study on the Bearing Capacity of the Sand Foundation Including the Dense Sand Layer (조밀한 층을 포함하는 사질 지반의 지지력에 관한 연구)

  • Park, Eun Young;Lee, Sang Duk;Kwon, Oh Yeoh;Hu, Chang Tack
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.13 no.2
    • /
    • pp.237-242
    • /
    • 1993
  • The bearing capacity of the sand foundation including a thin dense sand layer depends on the stiffiness, thickness and the location of the dense sand layer. In this paper was the influence of the dense sand layer on both the bearing capacity and the failure configuration is studied by means of K.E.M(Kinematic Element Method). K.E.M was implemented to get the excat solution starting from the upper bound of the analysis. The result show that the bearing capacity of the foundation and the failure configuration is greatly influenced by the dense sand layer, when the layer is located not deeper than 3/5 of the foundation width.

  • PDF

A Study on Design Method of Geogrid Encased Stone Colum for Settlement Reduction in Railroad (철도노반 침하저감을 위한 토목섬유 감쌈 쇄석말뚝 설계방안 고찰)

  • Lee, Dae-Young
    • Journal of the Korean Geosynthetics Society
    • /
    • v.13 no.3
    • /
    • pp.31-38
    • /
    • 2014
  • The geogrid encased stone column (GESC) system, which increases the confinement effect, has been developed to improve the load carrying capacity of stone columns. The resonable design method for calculating the geogrid ring tension force and ultimate bearing capacity that can be applied to the design of GESC is proposed. In order to calculate design procedure for GESC, two ultimate bearing capacities were compared. One is the ultimate bearing capacity measured using data of the field loading test in light railway site and the other is the ultimate bearing capacity using suggested design procedure of GESC. The results indicated that design method of GESC higher ultimate bearing capacities compared with field loading test.

Estimation of Bearing Capacity of Non-Displacement Piles in Sand Considering Pile Shape (모래지반에서 말뚝형태를 고려한 비배토말뚝의 지지력 산정)

  • Paik, Kyu-Ho;Lee, Jun-Hwan;Kim, Dae-Hong
    • Journal of the Korean Geotechnical Society
    • /
    • v.23 no.5
    • /
    • pp.101-110
    • /
    • 2007
  • In order to investigate the effect of the pile shape on the bearing capacity of non-displacement piles, a series of model pile load tests were performed using a calibration chamber and three model piles with different shape. Results of the model tests showed that the bearing capacity of tapered piles was affected by its taper angle as well as the stress states and relative density of soil. Based on the results of model pile load tests, a new design equation for estimation of the bearing capacity of non-displacement piles was proposed, and it takes into account the effect of the taper angles on the bearing capacity of non-displacement piles.

Evaluation of Bearing Capacity of Piled Raft Foundation on OC Clay Using Centrifuge and Numerical Modeling (원심모형 실험과 수치해석을 이용한 과압밀 지반에서의 말뚝지지 전면기초의 지지력 평가)

  • Park, Jin-Oh;Chao, Yun-Wook;Kim, Dong-Sao
    • Journal of the Korean Geotechnical Society
    • /
    • v.25 no.7
    • /
    • pp.23-33
    • /
    • 2009
  • In this study the characteristics of piled raft was investigated by using both centrifuge and numerical modeling. The ultimate bearing capacities of single pile, unpiled raft, freestanding pile group and piled raft were compared in order to investigate load sharing of each element : pile and raft. The comparison determined parameters to simply evaluate the ultimate bearing capacity of piled raft. Centrifuge test results were simulated by numerical simulation to verify the parameters.