Limiting tip and side resistance: fact or fallacy?

Keyword(s):  
2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Zhijun Zhou ◽  
Shanshan Zhu ◽  
Xiang Kong ◽  
Jiangtao Lei ◽  
Tong Liu

The settlement calculation of postgrouting piles is complex and depends on the calculation method and parameters. Static load tests were conducted to compare the settlement characteristics of nongrouting and postgrouting piles, and three vital parameters in the layer-wise summation method were revised to predict the settlement of postgrouting piles. The elastic compression coefficient was deduced based on the Mindlin–Geddes method by considering the influence of the change in the pile side resistance distribution and end resistance ratio on the elastic compression after grouting. The relationship between the compression modulus and soil gravity stress and cone penetration resistance were established, respectively, using experimental data. The optimum value of the settlement empirical coefficient was determined using regional data. Finally, we used the postgrouting pile of the Wuqi–Dingbian expressway as a practical example. The results obtained from the layer-wise summation method after parametric optimization were close to the measured values. The results of this study provide reference data and guidance for the settlement calculation of postgrouting piles in this area.


2021 ◽  
Vol 68 ◽  
pp. 940-950
Author(s):  
Sendong Ren ◽  
Yunwu Ma ◽  
Ninshu Ma ◽  
Shuhei Saeki ◽  
Yoshiaki Iwamoto

2012 ◽  
Vol 170-173 ◽  
pp. 474-477
Author(s):  
Ying Jie Zheng ◽  
Lian Xiang Li ◽  
Shu Cai Li ◽  
Xue Dai

A pile-soil interface model was established. The model considered the influence of interface lateral stress on the interface mechanics parameters. In this model the ultimate shear stress and the max tangential stiffness in loading process were related with pile lateral stress ratio. The influence of loading model on pile side resistance can be considered in this model. With the model, the interface parameters under pressing down at pile top can be got from those under pushing at pile bottom load. The suggested model was applied to analyze an O-cell pile test case. The analysis results show that the bearing capacity under loading press at pile top is higher than that under pushing at pile bottom, and the increase extent is agree with practical experience. It is also confirmed that the model is applicable and effective.


2007 ◽  
Vol 44 (11) ◽  
pp. 1378-1390 ◽  
Author(s):  
C. Cherubini ◽  
G. Vessia

The evaluation of the pile–soil adhesion plays a fundamental role in the estimation of the side resistance for total stress analysis. Over the years, researchers have presented proposals for adhesion factor formulations even though only a few of them have shown a certain agreement in numerical and (or) methodological terms. Hence, several real-size experimental analyses have improved the understanding of the pile–soil adhesion phenomenon and mechanism. Nevertheless, the undrained shear strength (cu) values depend on the experimental technique employed. Such results force engineers to make a difficult choice among various formulations. A reliability analysis is performed in this paper to take into consideration the variations in formulations and values of the side resistance of bored piles in clayey soils. This study involves piles having different lengths and diameters, which are supposed to be bored in Matera clays. Such soil is characterized by means of laboratory investigation campaign, and its mechanical and stochastic main features are reported here. Values of reliability index β are calculated by means of the first-order reliability method.


Author(s):  
Sendong Ren ◽  
Yunwu Ma ◽  
Ninshu Ma ◽  
Qian Chen ◽  
Haiyuan Wu

Abstract In the present research, a digital twin of coaxial one-side resistance spot welding (COS-RSW) was established for the real-time prediction of transient temperature field. A 3D model of COS-RSW joint was developed based on the in-house finite element (FE) code JWRIAN-SPOT. The experimental verified FE model was employed to generate the big data of temperature of COS-RSW process. Multiple dimension interpolation was applied to process database and output prediction. The FE model can predict the thermal cycle on COS-RSW joints under different parameter couples. The interpolation effect of individual welding parameters was discussed and a power weight judgement for welding time was essential to ensure accuracy. With the support of big data, the digital twin can provide visualization prediction of COS-RSW within 10 seconds, whereas numerical modelling needs at least 1 hour. The proposed application of digital twin has potential to improve the efficiency of process optimization in engineering.


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