Prediction of Ultimate Bearing Capacity of Long-Term Loaded Piles

doi:10.16183/j.cnki.jsjtu.2019.348

Abstract

Abstract:

To predict the ultimate bearing capacity of long-term loaded piles, the shortcomings of current empirical formulas of pile bearing capacity considering time effect are discussed. Based on the current research of the bearing capacity of static bearing piles in natural saturated clay, factors for the bearing capacity of long-term loaded old piles are analyzed. Then, based on analysis of the data from pile foundation bearing tests, the formula for calculating the ultimate bearing capacity of jacked piles considering the time effect and the current pile foundation technical code is proposed, in which the pile side resistance aging coefficient of pile side resistance is proposed, and some factors for the aging coefficient are discussed. Based on the experimental data, a method for calculating the parameters in the formula by using soil properties is proposed. The accuracy of the proposed method is verified by a field test. The results show that this pile side resistance aging coefficient can predict the bearing capacity of single pile under current code, increase the design value of the bearing capacity of old piles while ensuring safety. By using the undrained shear strength and plasticity index, the pile side resistance aging coefficient can be predicted.

Key words: old pile, ultimate bearing capacity, aging coefficient, undrained shear strength, field test

CLC Number:

TU473

LI Jingpei, XU Zihan. Prediction of Ultimate Bearing Capacity of Long-Term Loaded Piles[J]. Journal of Shanghai Jiao Tong University, 2021, 55(4): 380-386.

Figures/Tables 7

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土的类别	休止时间/d
砂土	7
粉土	10
非饱和黏性土	15
饱和黏性土	25

土层名称	H/m	γ/ (kN·m^-3)	e	c/kPa	φ/(°)	E_s/ MPa
杂填土	1.53	-	-	-	-	-
浜土	1.60	-	-	-	-	-
粉质黏土	1.75	18.9	1.052	25	31.7	5.46
淤泥质粉黏土	1.71	17.6	1.187	16	27.5	3.67
砂质粉土	2.38	18.7	1.003	2	32.5	10.94
淤泥质黏土	9.39	16.6	1.485	14	24.8	2.17
黏土	10.03	17.4	1.219	16	28.4	3.14
粉质黏土	8.93	17.8	1.065	16	31.9	4.07
砂质粉土	10.04	18.5	0.988	4	31.8	9.12
粉质黏土夹砂	10.97	17.5	0.980	17	31.7	4.10