scholarly journals Laboratory Model Test to Explore the Bearing Mechanism of Composite Foundation in the Loess Area

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Longfei Xu ◽  
Weijiang Xu ◽  
Aijun Zhang ◽  
Xiaolin Weng ◽  
Gaowen Zhao ◽  
...  
Keyword(s):  
Experimental Data ◽  
Model Test ◽  
Load Test ◽  
Composite Foundation ◽  
Tangent Modulus ◽  
Laboratory Model ◽  
Single Pile ◽  
Loess Area ◽  
Modulus Method ◽  
Laboratory Model Test

Pile composite foundation can make good use of the bearing capacity of the soil and pile, which is widely used in the Chinese northwest loess area. However, the theory of pile composite foundation is far from sufficient, hindering its long-term development. Aiming at this problem, a laboratory model test of pile composite foundation in the loess area was conducted to explore the common working mechanism and variations of each bearing stage. Besides, the settlement of the single pile composite foundation was calculated by using the modified tangent modulus method, and the result was compared with the experimental data. The main results of this paper are as follows: Both in the single pile and single pile composite foundation, loading-settlement curves showed a trend of “elastic to elastoplastic to plastic,” accompanied by the appearance of plummeting point. Influenced by the pile group effect, the loading-settlement curve of the group pile composite foundation showed a slow-varying trend without an obvious breakdown point. Pile axis stress increased with the growth of upper load. At the beginning of loading, the pile axis stress indicated such a distribution that stress on both ends of the pile was larger than that in the middle of the pile. When reaching a certain load, the location of the biggest pile axis stress transferred to the pile top, and the pile axis stress decreased gradually as the pile became deep. The side friction resistance in the static load test of the single pile was always positive, whereas in the composite foundation of a single pile and a group of piles, negative side resistance appeared in the upper side of the neutral point. Pile-soil stress ratio in the depth of 12 cm changed with the upper load. The outcome calculated by the modified tangent modulus method had a relatively better consistency with experimental data if the upper load was not too large.

scholarly journals Settlement Analysis of Saturated Tailings Dam Treated by CFG Pile Composite Foundation

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Jinxing Lai ◽  
Houquan Liu ◽  
Junling Qiu ◽  
Jianxun Chen
Keyword(s):  
Model Test ◽  
Deformation Modulus ◽  
Composite Foundation ◽  
Laboratory Model ◽  
Tailings Dam ◽  
Foundation Treatment ◽  
Building Foundation ◽  
Cfg Pile Composite Foundation ◽  
Laboratory Model Test ◽  
Cfg Pile

Cement fly ash gravel (CFG) pile composite foundation is an effective and economic foundation treatment approach, which is significant to building foundation, subgrade construction, and so forth. The present paper aims at investigating the settlement behaviors of saturated tailings dam soft ground under CFG pile composite foundation treatment, in which FEM and laboratory model test were utilized. The proposed findings demonstrate that CFG pile treatment is effective in reinforcing saturated tailings dam and loading has little influence on settlement of soil between piles. The variation of soil between piles settlement in FEM has a good agreement with the laboratory model test. Additionally, the cushion deformation modulus has a small effect on the composite foundation settlement, although the cushion thickness will generate certain influence on the settlement distribution of the composite foundation.

Laboratory Model Test of EPB Shield Tunneling in a Cobble-Rich Soil

2020 ◽  
Vol 146 (10) ◽  
pp. 04020112 ◽  
Author(s):  
Xiongyu Hu ◽  
Chuan He ◽  
Gabriel Walton ◽  
Yong Fang ◽  
Guanghui Dai
Keyword(s):  
Model Test ◽  
Laboratory Model ◽  
Shield Tunneling ◽  
Laboratory Model Test ◽  
Epb Shield

Design Method of Long-Short-Pile Composite Foundation Base on Tangent Modulus In Situ Loading Test Curve

2011 ◽  
Vol 243-249 ◽  
pp. 2314-2323 ◽  
Author(s):  
Peng Liu ◽  
Guang Hua Yang ◽  
Yu Cheng Zhang
Keyword(s):  
Design Method ◽  
Composite Foundation ◽  
Tangent Modulus ◽  
Loading Test ◽  
Undisturbed Soil ◽  
Foundation Base ◽  
Modulus Method ◽  
S Curve ◽  
Deformation Compatibility

The settlement of each part of the composite foundation, such as the foundation mat, cushion, soils and pile head, is recognized as equivalent under normal working conditions. On the basis of this, the corresponding load on long-short pile and soils can be derived easily from each individual p-s curve. The p-s curve of the composite foundation can be pictured in terms of the mutual actions of all the components mentioned above. and thus the corresponding settlement with load will be determined. Meanwhile, the p-s curve can be obtained via the undisturbed soil hyperbola tangent modulus method, which not only characters the nonlinear relationship between load and settlement very well, but also shows the deformation compatibility among those components. It is found that designed bearing capacity of soil is much higher than the reality based on usual design norms of composite foundation, while pile load is greater than the designed ones, which can be credited to the deformation compatibility of pile-soil not considered.

Ultimate bearing capacity of shallow foundations on sand with geogrid reinforcement

1993 ◽  
Vol 30 (3) ◽  
pp. 545-549 ◽  
Author(s):  
M.T. Omar ◽  
B.M. Das ◽  
V.K. Puri ◽  
S.C. Yen
Keyword(s):  
Bearing Capacity ◽  
Key Words ◽  
Model Test ◽  
Ultimate Bearing Capacity ◽  
Shallow Foundations ◽  
Shallow Foundation ◽  
Laboratory Model ◽  
Critical Depth ◽  
Test Results ◽  
Laboratory Model Test

Laboratory model test results for the ultimate bearing capacity of strip and square foundations supported by sand reinforced with geogrid layers have been presented. Based on the model test results, the critical depth of reinforcement and the dimensions of the geogrid layers for mobilizing the maximum bearing-capacity ratio have been determined and compared. Key words : bearing capacity, geogrid, model test, reinforced sand, shallow foundation.

Frost Heave and Thawing Settlement of Frozen Soils around Concrete Piles: A Laboratory Model Test

2019 ◽  
Vol 49 (2) ◽  
pp. 20180764
Author(s):  
Liyun Tang ◽  
Xiaogang Wang ◽  
Long Jin ◽  
Lijun Deng ◽  
Di Wu
Keyword(s):  
Model Test ◽  
Frost Heave ◽  
Laboratory Model ◽  
Frozen Soils ◽  
Concrete Piles ◽  
Laboratory Model Test

Laboratory Model Test Study of Tunnel Anchor

2014 ◽  
Vol 1065-1069 ◽  
pp. 333-336
Author(s):  
Bing Shen ◽  
Sai Qiong Long ◽  
Jun Chen ◽  
Yong Bing Li
Keyword(s):  
Model Test ◽  
Shear Failure ◽  
Failure Surface ◽  
Tensile Failure ◽  
Laboratory Model ◽  
Pull Out ◽  
Test Study ◽  
Cable Force ◽  
Anchor Design ◽  
Laboratory Model Test

A laboratory model test of tunnel anchor was conducted to investigate its pullout mechanism and bearing capacity. Surface and rock deformation, strain and stress were measured during the entire model test process. The results show that: under pull out load, tensile failure first occurs in top surface rock near the anchor, then shear failure occurs in anchor-rock interface and rock around the anchor. The failure surface is inverted cone from the anchor bottom. Under 50 times design cable force tunnel rock is in elastic stage, suggesting that current tunnel anchor design is quite conservative and can be further optimized.

Performance of embankments with and without reinforcement on soft subsoil

2002 ◽  
Vol 39 (4) ◽  
pp. 838-848 ◽  
Author(s):  
Jin-Chun Chai ◽  
Norihiko Miura ◽  
Shui-Long Shen
Keyword(s):  
Model Test ◽  
Case History ◽  
Laboratory Tests ◽  
Lateral Displacement ◽  
Excess Pore Pressure ◽  
Laboratory Model ◽  
Ground Field ◽  
Obvious Effect ◽  
Laboratory Model Test ◽  
Soft Subsoil

A case history of both reinforced and unreinforced embankments on soft subsoil built-to-failure is described and analyzed. The effect of geotextile reinforcements on embankment behavior is discussed by comparing the field and numerical analysis results of cases with and without reinforcement. The results of a laboratory model test on the behavior of embankments on soft subsoil are discussed. Both field and laboratory tests, as well as analysis results, indicate that the reinforcement had a positive effect on embankment stability. However, at a working state (for a factor of safety of FS = 1.2~1.3) the reinforcement did not have an obvious effect on the subsoil response. The effect of reinforcement on subsoil deformation could be noticed only when the unreinforced embankment was close to failure. The laboratory model test results indicated that if the reinforcement is stiff and strong enough, the effect of reinforcement is considerable. It is suggested that although the geotextile has a beneficial effect on embankment over soft subsoil due to its relative lower stiffness, to achieve a substantial improvement on embankment behavior, the stiffer and stronger reinforcements should be used. This case history also demonstrated that the rate of lateral displacement and excess pore pressure development are sensitive indicators of the stability of embankment on soft subsoil.Key words: embankment, reinforcement, soft ground, field tests, laboratory tests, FEM analysis.

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