Experimental Comparison Study on Behavior of Combined Piles Composite Foundation

2011 ◽  
Vol 90-93 ◽  
pp. 264-270 ◽  
Author(s):  
De Quan Zhou ◽  
Hong Li Liu
Keyword(s):  
Economic Effects ◽  
Composite Foundation ◽  
Experimental Comparison ◽  
Plastic State ◽  
Loading Test ◽  
Total Load ◽  
Soil Stress ◽  
S Curve ◽  
Control Principle ◽  
Plate Loading

The combined pile composite foundation has the advantages of good technical and economic effects, yet there are no mature analysis methods to practise in design and test at present. This paper has studied the three and four-element composite foundation by the plate loading test, in which the pressure cells, pressure manometers and sensors are laid on the top of the piles and soil. The results show that the stress on the top of piles and soil increases with the increase of total load, the increasing rate being directly proportional to the strength or relative rigidity of piles and soil. The various increasing rates of piles and soil stress versus load make great difference between the three and four-element composite foundation in the variation of the load sharing ratio and the stress ratio versus load. The settlement of the combined piles composite foundation varies gradually with pressure, and the p-s curve may be simulated by hyperbola curve so as to establish the failure criterion and obtain tangent modulus. As the pressure increases, the inter-pile soil enters plastic state earlier than the piles, so the latter have to bear majority of the load, which makes the settlement rise. The composite foundation should be designed according to settlement-control principle.

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.

scholarly journals Laboratory Plate Loading Test on Calcareous Sands from a Hydraulic fill Reef Island

2021 ◽  
Author(s):  
Xing Wang ◽  
YANG WU ◽  
Jie Cui ◽  
Chang-qi Zhu ◽  
Xin-zhi Wang
Keyword(s):  
Bearing Capacity ◽  
Deformation Modulus ◽  
Fine Sand ◽  
Medium Sand ◽  
Calcareous Sand ◽  
Loading Test ◽  
Moisture Condition ◽  
Hydraulic Fill ◽  
Deformation Properties ◽  
Plate Loading

Abstract The landforms and vertical strata distribution characteristics of Yongxing Island show that the reclaimed reef island is characterized by soft upper strata (calcareous sand) and hard lower strata (reef limestone). In this study, a series of plate loading tests was conducted to examine the influences of particle gradation, compactness, and moisture condition on the bearing mechanism and deformation properties of the calcareous sand foundation. When the foundation is shallowly buried, the relative density range corresponding to a calcareous sand foundation exhibiting local shear failure is narrower than that of a terrigenous sand foundation. For the same compactness, dry calcareous medium sand has a much larger bearing capacity and deformation modulus than dry calcareous fine sand. The effect of water on the bearing capacity of the calcareous medium sand is greater than the effect on calcareous fine sand. Its weak cementation and low permeability make the initial deformation of saturated calcareous fine sand slightly smaller than that under dry conditions. The stress dispersion angle of the calcareous medium sand foundation is 52°, which is larger than that of terrigenous sand. A larger stress dispersion angle leads to a higher bearing capacity and deformation modulus than those of terrigenous sand.

Study and Analysis on Pile-Soil Stress Ratio of the Composite Foundation of Cement-Soil Mixing Pile under Flexible Foundation

2011 ◽  
Vol 335-336 ◽  
pp. 1145-1150
Author(s):  
Xiao Rong Yang ◽  
Lei Yu Zhang ◽  
Hai Chao Li ◽  
Li Ying Dong
Keyword(s):  
Stress Ratio ◽  
Soft Soil ◽  
Composite Foundation ◽  
Soil Mixing ◽  
Soil Stress ◽  
Soil Foundation ◽  
Soft Soil Foundation ◽  
Flexible Foundation ◽  
Cement Soil ◽  
Friction Pile

In order to analyze the characteristics of pile-soil stress ratio of the composite foundation of cement-soil mixing pile under flexible foundation, this paper points out the displacement mode of friction pile; According to the deformation characteristic of friction pile, ascertain the neutral point of composite foundation. And this paper also derives the exact formula about length-stress ratio which addresses the problem of soft soil foundation according to the deformation co-ordination conditions of the pile composite foundation. The calculation of actual example proves that the formula about pile-soil stress ratio is in accordance with actual measurement number. The pile-soil stress ratio which addresses the problem of soft soil foundation is generally between 2~4. If other conditions keep invariable, pile-soil stress ratio become big when cushion modulus become big. Cushion modulus effect the length-stress ratio greatly.

Shipboard Power System Restoration Using S-Curve Inertia Weight Particle Swarm Optimization

2013 ◽  
Vol 433-435 ◽  
pp. 1226-1229
Author(s):  
Yang Chen ◽  
Yan Cheng Liu ◽  
Chuan Wang ◽  
Liang Xiong Shen
Keyword(s):  
Particle Swarm Optimization ◽  
Power System ◽  
Particle Swarm ◽  
Swarm Optimization ◽  
Total Load ◽  
Power System Restoration ◽  
Inertia Weight ◽  
Shipboard Power System ◽  
Shipboard Power ◽  
S Curve

The shipboard power system (SPS) supplies energy to sophisticated systems for weapons, communications, navigation and operation. It is critical for the system to be reconfigurable for the purpose of survivability and reliability. The present paper proposes a new variation of PSO model for restoration of shipboard power system. A new inertia weight of S-Curve Decreasing variation is introduced. Particle Swarm Optimization with S-Curve Decreasing Inertia Weight (SDW-PSO) approach can improve the speed of convergence as well as fine tune the search. The proposed Particle Swarm Optimization algorithm enables to find the optimal combination of loads that can be supplied after the occurrence of the fault, in which the priorities of the loads and the constraint of balance between the total load and total generation are considered.

A Field Experimental Study of Composite Foundation with Rammed Soil-Cement Pile in Collapsible Loess Area

2014 ◽  
Vol 1030-1032 ◽  
pp. 969-973 ◽  
Author(s):  
Hai Jian Sun ◽  
Shi You Zhang
Keyword(s):  
Composite Foundation ◽  
Engineering Properties ◽  
Test Results ◽  
Loading Test ◽  
Foundation Soil ◽  
Loess Area ◽  
Soil Cement ◽  
Static Loading Test ◽  
Natural Foundation ◽  
Field Static

Natural foundation in loess areas is collapsible; however, composite foundation with rammed soil-cement pile can be used to meet the load requirements of the building. Immersion-compression test and field static loading test were carried out to measure the treatment effect. The test results showed that: the collapsible of loess foundation can be eliminated by treatment with rammed soil-cement pile when the loading pressure is between 200 to 500 kPa. Engineering properties of the foundation soil between piles are improved. The parameters improve more obvious with the pile spacing getting smaller. The bearing capacity of composite foundation increased to 291 kPa, compared with natural loess foundation. The research results can be applied to design and construction of compacted soil cement pile composite foundation in loess area.

Finite Element Analysis of Cushion Thickness and Ultimate Bearing Capacity of Lime Soil Pile Composite Foundation

2012 ◽  
Vol 594-597 ◽  
pp. 565-569
Author(s):  
Zi Sen Wei ◽  
Yong Mou Zhang ◽  
Dong Hui Peng
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Stress Ratio ◽  
Shear Failure ◽  
Ultimate Bearing Capacity ◽  
Load Test ◽  
Composite Foundation ◽  
Static Load Test ◽  
Rate Of Increase ◽  
Soil Stress

The static load test of composite foundation was simulated by using the nonlinear finite element programs, and the changes of the pile-soil stress ratio and the pile and soil settlements as well as the plastic deformation of composite foundation were analyzed. The simulation results show that: the cushion of flexible pile composite foundation can effectively regulate the pile-soil stress ratio and make the bearing capacity of the lime soil pile and the soil between piles give full play at the same time. The cushion has a distinct role in reducing the pile settlements, however, has little effect in reducing the soil settlements. The reasonable cushion thickness is about 300mm. The composite foundation will emerge local shear failure when it reaches the ultimate bearing capacity. Reducing the pile spacing can increase the ultimate bearing capacity, and the rate of increase shows a gradually increasing trend.

Study of Low Strength Pile Composite Foundation Deformation & Stability Calculation Method

2012 ◽  
Vol 170-173 ◽  
pp. 545-556 ◽  
Author(s):  
Chao Guo ◽  
Shi Wei Xiao ◽  
Ze Lian Chen
Keyword(s):  
Beam Theory ◽  
Composite Foundation ◽  
Future Research ◽  
Deformation Model ◽  
Stability Calculation ◽  
Strain Compatibility ◽  
Compression Deformation ◽  
Soil Stress ◽  
Foundation Deformation ◽  
Low Strength

A group of deformation and stability calculation equations on the low strength pile (LSP) composite foundation is deduced from the LSP composite foundation deformation model. The stress-strain compatibility equations are yielded, in which the interactions among the pile, soils and cushions are considered. At the same time, the pile-soil stress ratio and the equal-settlement-surface (ESS) analytical solution are also yielded. Furthermore, the pile and its surrounding soil stress distribution regulation, compression deformation, the up- pricking-deformation of the cushion and the under-pricking-deformation of the subsoil are all obtained. Through the summary of the composite foundation subsoil settlement and the soil among piles compression deformation, the whole settlement of the composite foundation is deduced. In the above equations, the pile stability and flexibility are analyzed using elastic foundation beam theory. The methods put forward here can be a significant reference for the future research and design of the LSP composite foundation.

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