scholarly journals Numerical Simulation Study Of Squeezed Branch Piles Based On Post-grouting Technology

2021 ◽  
Vol 292 ◽  
pp. 01038
Author(s):  
LiXing Ma ◽  
ZhuoPeng Shi ◽  
Kai Han ◽  
PengFei Chang ◽  
XiaoDong He

The squeezed branch pile has strong resistance to pressure, pullout and horizontal force, and it also has excellent stability, which makes it widely used in the field of electrical engineering. Based on the ABAQUS, the paper simulates the vertical bearing situation of post-grouting squeezed branch piles, by setting up Set two comparisons of single pile and squeezed branch pile, the bearing capacity, load transfer mechanism and failure mode of post-grouting squeezed branch piles were comprehensively analyzed and compared. Studies have shown that the bearing capacity of the squeezed branch piles with post-grouting technology has increased by 68.1% compared with the traditional squeezed branch piles, and the bearing characteristics of the branches have changed greatly. In this process, the end-bearing function of the branch plate is fully exerted, and the high load-bearing capacity of the grouted strata soil is used to reduce the settlement.

Friction ◽  
2021 ◽  
Author(s):  
Luyao Gao ◽  
Xiaoduo Zhao ◽  
Shuanhong Ma ◽  
Zhengfeng Ma ◽  
Meirong Cai ◽  
...  

AbstractSilicone elastomers-based materials have been extensively involved in the field of biomedical devices, while their use is extremely restricted due to the poor surface lubricity and inherent hydrophobicity. This paper describes a novel strategy for generating a robust layered soft matter lubrication coating on the surface of the polydimethylsiloxane (PDMS) silicone elastomer, by entangling thick polyzwitterionic polyelectrolyte brush of poly (sulfobetaine methacrylate) (PSBMA) into the sub-surface of the initiator-embedded stiff hydrogel coating layer of P(AAm-co-AA-co-HEMA-Br)/Fe, to achieve a unified low friction and high load-bearing properties. Meanwhile, the stiff hydrogel layer with controllable thickness is covalently anchored on the surface of PDMS by adding iron powder to provide catalytic sites through surface catalytically initiated radical polymerization (SCIRP) method and provides high load-bearing capacity, while the topmost brush/hydrogel composite layer is highly effective for aqueous lubrication. Their synergy effects are capable of attaining low friction coefficient (COFs) under wide range of loaded condition in water environment with steel ball as sliding pair. Furthermore, the influence of mechanical modulus of the stiff hydrogel layer on the lubrication performance of layered coating is investigated, for which the COF is the lowest only when the modulus of the stiff hydrogel layer well matches the PDMS substrate. Surprisingly, the COF of the modified PDMS could remain low friction (COF < 0.05) stably after encountering 50,000 sliding cycles under 10 N load. Finally, the surface wear characterizations prove the robustness of the layered lubricating coating. This work provides a new route for engineering lubricious silicon elastomer with low friction, high load-bearing capacity, and considerable durability.


2018 ◽  
Vol 10 (3) ◽  
pp. 2965-2975 ◽  
Author(s):  
Zechao Li ◽  
Yongxin Wang ◽  
Xiaoying Cheng ◽  
Zhixiang Zeng ◽  
Jinlong Li ◽  
...  

2020 ◽  
Vol 23 (11) ◽  
pp. 2276-2291
Author(s):  
Rui Pang ◽  
Yibo Zhang ◽  
Longji Dang ◽  
Lanbo Zhang ◽  
Shuting Liang

This article proposes a new type of discrete connected precast reinforced concrete diaphragm floor system that consists of precast flat slabs and slab joint connectors. An experimental investigation of discrete connected new-type precast reinforced concrete diaphragm under a vertical distributed static load was conducted, and the effect of slab joint connectors on the load-bearing capacity was evaluated. Then, a finite element analysis of discrete connected new-type precast reinforced concrete diaphragm, precast reinforced concrete floors without slab connectors, and cast-in-situ reinforced concrete floor were performed to understand their working mechanism and determine the differences in load-bearing behavior. The results indicate that the load-bearing capacity and stiffness of discrete connected new-type precast reinforced concrete diaphragm increase considerably as the hairpin and cover plate hybrid slab joint connectors can efficiently connect adjacent precast slabs and enable them to work together under a vertical load by transmitting the shear and moment forces in the orthogonal slab laying direction. The deflection of discrete connected new-type precast reinforced concrete diaphragm in orthogonal slab laying direction is mainly caused by the opening deformation of the slab joint and the rotational deformation of the precast slabs. This flexural deformation feature can provide reference for establishing the bending stiffness analytical model of discrete connected new-type precast reinforced concrete diaphragm in orthogonal slab laying direction, which is vitally important for foundation of the vertical bearing capacity and deformation calculation method. The deflection and crack distribution patterns infer that the discrete connected new-type precast reinforced concrete diaphragm processes the deformation characteristic of two-way slab floor, which can provide a basis for the theoretical analysis of discrete connected new-type precast reinforced concrete diaphragm.


2021 ◽  
Author(s):  
Bin Lei ◽  
Wengui Li ◽  
Zhuo Tang ◽  
Fuzhi Yang

The application of recycled compound concrete made of demolished concrete lumps (DCLs) and fresh normal concrete in pier foundation can effectively improve the utilization efficiency of construction waste resources. In this study, two prefabricated pier foundations based on recycled compound concrete (dimension of Ø800 × 2500 mm and Ø1000 × 2500 mm) and two cast-in-place pier foundations based on ordinary concrete (dimension of Ø800 × 2500 mm and Ø1000 × 2500 mm) were tested. Special attention was devoted to the load-settlement curve characteristics of the precast pier foundation of compound concrete, the load transfer law of the pier-soil system, the soil pressure distribution at the bottom of the pier, and the failure mode. The results showed that the Q-S curve of precast concrete pier foundation made of recycled compound concrete is slow deformation at loading, which is consistent with that of cast-in-place concrete pier foundation. The load transfer theory of pier-soil system is established, and its accuracy is verified by experimental analysis. The precast foundation of recycled compound concrete is the same as the cast-in-place foundation of ordinary concrete. The failure form of prefabricated pier foundation made of recycled compound concrete was a local shear failure, while the failure form of ordinary concrete cast-in-place pier foundation was piercing-type shear failure. The feasibility of relevant theoretical methods for calculating the vertical ultimate bearing capacity is examined.


2016 ◽  
Vol 10 (1) ◽  
pp. 813-825
Author(s):  
Lina Xu ◽  
Xuedong Guo ◽  
Lei Nie ◽  
Yongmei Qian

In this paper, a theoretical relationship between the load and settlement of a single pile in an Osterberg-Cell test was developed, considering the joint action of piles and soil and a detailed deformation analysis was conducted based on the load transfer theory of piles. The shear test and the compression test were used to determine the load transfer parameters for soil layers around a pile at various depths as well as the parameters for pile-tip soils. Based on this method, a simulation analysis program was applied to determine the location of the balance point in the Osterberg-Cell test to provide a reference for the test design. The analytical methods presented in this paper could be considered practical because the results from the simulation test and on-site measurement indicate that the theoretically predicted result is consistent with the measurements. A reasonable selection of the location of the hydraulic jack-like device (O-cell) could maximize the bearing capacity of testing piles to obtain a more accurate ultimate bearing capacity. This study provides a reference for the design of the Osterberg-Cell test as well as pile foundations.


2019 ◽  
Vol 52 (1) ◽  
pp. 38-52
Author(s):  
Pooya Saremi ◽  
Wei Lu ◽  
Jari Puttonen ◽  
Dan Pada ◽  
Jyrki Kesti

The load-carrying capacity of a K-type joint inside a floor truss is studied both experimentally and numerically. The joint tested is a scaled-down, isolated joint. The tubular braces, plate chord, and division plate are made of SSAB Domex steel. Comparison of load displacement curves received by finite element analyses with curves obtained from tests confirms that numerical models describe joint behaviour reasonable. The paper demonstrates that joints with high load-bearing capacity can be investigated experimentally by scaling the dimensions of the joint down when testing devices can affect the required capacity of the joint. The results presented can also be used for optimizing failure mechanism of similar joints in practice.


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