Prediction of Vertical Ultimate Bearing Capacity in Piles Based on the Improved Hyperbolic Model

2011 ◽  
Vol 250-253 ◽  
pp. 2271-2275
Author(s):  
Cheng Wang ◽  
Qi Zhang
Keyword(s):  
Bearing Capacity ◽  
Ultimate Bearing Capacity ◽  
Load Test ◽  
Hyperbolic Model ◽  
Maximum Point ◽  
Static Load Test ◽  
Hyperbolic Curve ◽  
The Mathematical Model ◽  
Test Pile

Vertical static load test is widely used in the determination of pile bearing capacity, the mathematical model used to fit test pile data in determining the bearing capacity is essential. From the perspective of analytic geometry, the paper analyzes the traditional method of hyperbola, of which the asymptotic line of equilateral hyperbola was used to determine the ultimate bearing capacity. By extending the equal-axed conditions, a more general form of hyperbolic equation is derived and feasibility of such method is also analyzed, which indicates that the maximum point of curvature in such hyperbolic curve can determine the ultimate bearing capacity and such method is proved to be reasonable in practical projects.

scholarly journals Static Load Test and Numerical Analysis of Influencing Factors of the Ultimate Bearing Capacity of PHC Pipe Piles in Multilayer Soil

2021 ◽  
Vol 13 (23) ◽  
pp. 13166
Author(s):  
Xusen Li ◽  
Jiaqiang Zhang ◽  
Hao Xu ◽  
Zhenwu Shi ◽  
Qingfei Gao
Keyword(s):  
Numerical Analysis ◽  
Bearing Capacity ◽  
Influencing Factors ◽  
Static Load ◽  
Young Modulus ◽  
Ultimate Bearing Capacity ◽  
Load Test ◽  
Freezing Stress ◽  
Static Load Test ◽  
Tip Resistance

Prestressed high-strength concrete (PHC) pipe piles have been widely used in engineering fields in recent years; however, the influencing factors of their ultimate bearing capacity (UBC) in multilayer soil need to be further studied. In this paper, a static load test (SLT) and numerical analysis are performed to obtain the load transfer and key UBC factors of pipe piles. The results show that the UBC of the test pile is mainly provided by the pile shaft resistance (PSR), but the pile tip resistance (PTR) cannot be ignored. Many factors can change the UBC of pipe piles, but their effects are different. The UBC of the pipe pile is linearly related to the friction coefficient and the outer-to-inner diameter ratio. Changes in the pile length make the UBC increase sharply. Low temperatures can produce freezing stress at the pile–soil interface. The effect of changing the Young modulus of pile tip soil is relatively small.

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.

Testing Research of Fiber Bragg Grating Strain Sensor Embedded in Bored Pile

2014 ◽  
Vol 599-601 ◽  
pp. 1085-1089
Author(s):  
Mian Huang ◽  
Yong Hong Wu ◽  
Yuan Yu Guan ◽  
Ying Na Li ◽  
Tao Xie ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Fiber Bragg Grating ◽  
Axial Strain ◽  
Load Test ◽  
Bragg Grating ◽  
Static Load Test ◽  
Bored Pile ◽  
Pull Out ◽  
Starting Point ◽  
Test Pile

Reinforced concrete piles are used when structures are constructed on soft ground, because it is necessary to transfer the loads into deeper strata with a sufficient bearing capacity. With the purpose of receiving more precise information about the pile features, four fiber Bragg grating strain sensors are embedded at different levels of the pile to measure the strain distribution during straining and pull-out tests. Test Pile vertical uplift static load test results show that, settlement of the test pile is steep variations, the steep rise starting point corresponding to the load of 3300 kN for the Uplift Ultimate Bearing capacity, the corresponding uplift amount is 12.45 mm; 4.4 m, 7.2 m, 11.0 m and 14.5 m sections axial strain were 115 με, 42 με, 6 με and-3 με. Maximum loading capacity is 3600 kN, the corresponding uplift amount is 30.13mm; 4.4 m, 7.2 m, 11.0 m and 14.5 m sections axial strain were 142 με, 61 με, 7 με and-1 με.

The Review on the Modified Exponential Model in the Fitting of Loading-Settlement Curves of Single Pile

2014 ◽  
Vol 501-504 ◽  
pp. 892-904
Author(s):  
Yu Chuan Shuan ◽  
Bo Yang Ding ◽  
Ming Ouyang
Keyword(s):  
Static Load ◽  
Exponential Model ◽  
Measured Data ◽  
Load Test ◽  
Hyperbolic Model ◽  
Single Pile ◽  
Static Load Test ◽  
Single Piles ◽  
Test Pile ◽  
Better Than

According to optimized fitting analysis for measured data in static load test of 22 different types of single piles, a new modified exponential model was proposed by authors in this paper. In comparison between the hyperbolic model and the integrated exponential curve model, the correlativity coefficients R of the modified exponential model were over 0.996. The fitting effect of the model of proposed in this paper is better than that of other models above-mentioned. The deviations between fitting and measured data in static load test for single pile was small, especially, in the tail pasts of fitting curves, the mean deviations of 2 test pile given in the paper are 1.61% and 1.99% respectively. The modified exponential model can be better described Q-S curves of single piles. It can be used to better evaluate the ultimate bearing capacity of single piles.

Assessment of CPTU and static load test methods for predicting ultimate bearing capacity of pile

2016 ◽  
Vol 35 (5) ◽  
pp. 738-745 ◽  
Author(s):  
Zhaoyu Wang ◽  
Nan Zhang ◽  
Guojun Cai ◽  
Qi Li ◽  
Jiajia Wang
Keyword(s):  
Bearing Capacity ◽  
Static Load ◽  
Test Methods ◽  
Ultimate Bearing Capacity ◽  
Load Test ◽  
Static Load Test

scholarly journals Static Load Test on Trapezoidal Filling Structure of Crushed Concrete Particles Reinforced with Waste Tire Slices

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Fang Tong ◽  
Qiang Ma ◽  
Bin Hu ◽  
Zhenyi Zheng
Keyword(s):  
Bearing Capacity ◽  
Earth Pressure ◽  
Bottom Layer ◽  
Ultimate Bearing Capacity ◽  
Load Test ◽  
Static Load Test ◽  
Waste Tire ◽  
Crushed Concrete ◽  
The Earth ◽  
Total Settlement

In this paper, a series of model tests about the trapezoidal filling structures filled with tire reinforced concrete particles has been conducted to study their stability and the ultimate bearing capacity. The effects of the reinforcing tire slices on the global stability and ultimate bearing capacity of the model were investigated, the results show that the tire slices reinforcement can reduce the total settlement of the trapezoidal filling structure, and the ultimate bearing capacity of the reinforced trapezoidal filling structure with tire slices is obviously improved. Among them, the settlements of crushed concrete particles reinforced with bottom layer, top layer, and two layers (both bottom layer and top layer) waste tire slices are 11.5%, 37.7%, and 46.2% less than that of unreinforcement, respectively. Compared with unreinforcement, when the top layer of the model is reinforced with tire slices, the Earth pressure values at the top layer and the bottom layer are reduced by 21.1% and 22.7%, respectively; the Earth pressure values at the top layer and the bottom layer are reduced 6.3% and 14.3%, respectively, when the bottom layer of the model is reinforced with tire slices, and the Earth pressure values at the top layer and the bottom layer are reduced 23.4% and 32.9%, respectively, when the two layers of the model are reinforced with tire slices. The sliding surface of the pure concrete particles filled trapezoidal structure is continuous and runs through the whole trapezoidal filling structure slope; the sliding zone of reinforced trapezoidal filling structure with tire slices decreases with the laying of tire slices.

scholarly journals Determination of Piles Bearing Capacity using Empirical Methods and (AllPile 6) Software -Cases studies Portsudan and Khartoum Cities

2021 ◽  
pp. 113-121
Keyword(s):  
Bearing Capacity ◽  
Static Load ◽  
Computer Software ◽  
Load Test ◽  
Empirical Methods ◽  
Static Load Test ◽  
Concrete Piles ◽  
Cases Study ◽  
Pile Load Test

Different methods have been used to determine the pile bearing capacity such as static equations, dynamic equations, empirical methods (EMs), numerical methods, computer software programs, and the pile static load test, these methods were giving different values for pile bearing capacity. In this paper, three empirical methods (Ems) have been selected (Brinch-Hansen, Chin-Kondner, and Decourt) and (AllPile 6) software (AP) has been applied to determine the capacity load of piles for six cases study of drilled concrete piles with a diameter ranging from 800 mm to 1500mm and embedded length ranged 10.5m to 26m. Four of those six piles are located at Portsudan city near the red seacoast and two piles are located in Khartoum city. The results of the pile bearing capacity (PC) calculations obtained using the above-mentioned different methods were compared with results produced by the pile load test. In all six cases study, the settlement of piles was limited, settlement failure was not reached. The results show that the AllPile 6 (AP) and the three mentioned empirical methods (Ems) gave reasonable piles bearing capacity, the (AP) and (BHM) gave the better result than the CKM and DM. While (DM) gave results similar to results determined using the (CKM). However, it was not preferred to use the (CKM) and (DM), unless the failure settlement has occurred in the pile load test.

Research on Settlement and Bearing Capacity of Y-Section Pile Considering Abnormality Effect

2013 ◽  
Vol 838-841 ◽  
pp. 935-939
Author(s):  
Xin Quan Wang ◽  
Xin Jiang Wei ◽  
An Yuan Liu ◽  
Juan Liao ◽  
Lian Wei Ren
Keyword(s):  
Bearing Capacity ◽  
Constant Load ◽  
Ultimate Bearing Capacity ◽  
Load Test ◽  
Additional Stress ◽  
Static Load Test ◽  
Stress Coefficient ◽  
Tip Resistance ◽  
Side Friction ◽  
Good Agreement

The side friction of Y-section pile is non-uniform distributed along its inverted arch arc, the load - settlement law of Y-section pile distinguishes to the traditional piles' as there is abnormality effect of side friction. Computation theory of settlement and ultimate bearing capacity needs to be studied. Calculate the settlement under different loads based on the model of skin friction, ultimate tip resistance and additional stress coefficient, and then predict ultimate bearing capacity by loads-settlement laws, the theoretical values of settlement and ultimate bearing capacity are in good agreement with the results of Static load test. The influences of five variables R, θ, δ, s, and L on settlement of Y-section file are analyzed, the settlement of Y-section pile under the constant load decreases with the increase of R, δ, s, δ and increases with the increase of θ. The influences of Relevant parameters on ultimate bearing capacity are also analyzed, the ultimate bearing capacity of Y-section pile decreases with the increase of θ and increases with the increase of R, δ, s and L.

Study on Vertical Bearing Capacity and Time Effect of the Jacked-in PHC Pipe Pile in the Cohesive Soil Area

2011 ◽  
Vol 368-373 ◽  
pp. 2706-2710
Author(s):  
Hong Liang Zuo ◽  
Lei Wang ◽  
Hong Ying Gao ◽  
Liang Guo
Keyword(s):  
Bearing Capacity ◽  
Cohesive Soil ◽  
Ultimate Bearing Capacity ◽  
Time Effect ◽  
Load Test ◽  
Static Load Test ◽  
Empirical Coefficient ◽  
Pipe Pile ◽  
Vertical Bearing ◽  
Vertical Bearing Capacity

The static load test of 34 jacked-in PHC pipe piles of medium length are performed in the cohesive soil area, the relationship between the vertical ultimate bearing capacity and the final pressure, and the time effect of vertical bearing capacity of the jacked-in PHC pipe pile are studied. The data of static load test is analyzed statistically with software SPSS, the regional empirical coefficient about the vertical ultimate bearing capacity and final pressure, and the time effect formula about vertical bearing capacity of the jacked-in PHC pipe pile in the cohesive area are obtained. According to the regional empirical coefficient, the pile pressing machine and counterweight can be chosen reasonably and the vertical ultimate bearing capacity of single pile can also be estimated rapidly, then we can instruct the design and construction of the jacked-in PHC pipe pile. According to the time effect formula, the vertical bearing capacity at different periods of the jacked-in PHC pipe pile can be obtained, the cost of the foundation engineering can be reduced by considering the time effect influence to the vertical bearing capacity of the jacked-in PHC pipe pile.

scholarly journals Determination of bearing capacity of shallow foundations without using superposition approximation

2003 ◽  
Vol 40 (2) ◽  
pp. 450-459 ◽  
Author(s):  
D Y Zhu ◽  
C F Lee ◽  
K T Law
Keyword(s):  
Bearing Capacity ◽  
Field Method ◽  
Ultimate Bearing Capacity ◽  
Shallow Foundation ◽  
Closed Form Expression ◽  
Safe Side ◽  
Superposition Approximation ◽  
Bearing Capacity Factor ◽  
Rigorous Procedure

The Terzaghi superposition assumption has been widely used to determine the bearing capacity of shallow footings. Although this assumption always errs on the safe side, a rigorous procedure to calculate the bearing capacity is still of engineering value. This paper presents such a procedure that is free from errors as a result of the superposition assumption. It demonstrates that the ultimate bearing capacity can be precisely expressed by the Terzaghi equation, except that the bearing capacity factor Nγ is dependent upon the surcharge ratio. A recently developed numerical method, i.e., the critical slip field method, is used to calculate the modification coefficient for modifying Nγ. It is found that this modification coefficient increases with the surcharge ratio at small values of surcharge ratio and then remains constant for large values of surcharge ratio. However, the errors invoked by the superposition assumption do not exceed 10%. On the basis of numerical calculations, a simple closed-form expression of the modification coefficient is proposed that yields the theoretically rigorous ultimate bearing capacity. In the later part of the paper, errors in bearing capacity calculations owing to the use of conventional procedures are analyzed. It is concluded that the continued use of conventional procedures is justified, but the inherent errors should not be neglected in assessing the performance of shallow foundations.Key words: shallow foundation, strip footing, ultimate bearing capacity, critical slip field.

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