scholarly journals Field Experiment Research of the Polycystic Aeration Bolt: Model Design and Anchorage Mechanism

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Wen Xiang Peng ◽  
Ming Kai Xu ◽  
Yi Fan Chen ◽  
Zheng Hao Chen ◽  
Zhuo Yang
Keyword(s):  
Bearing Capacity ◽  
Structural Design ◽  
Soft Soil ◽  
Test Results ◽  
Foundation Pit ◽  
Design Scheme ◽  
Pull Out ◽  
Practical Engineering ◽  
New Type ◽  
Engineering Cost

As a new type of bolt, the polycystic aeration bolt has a broad application prospect in soft soil area; however, its design and production are still in the stage of constant exploration and improvement. From the perspective of bolt material and engineering cost, the important components of the polycystic aeration bolt were analyzed by combination with the existing bolt models, and a new structural design scheme of a kind of polycystic aeration bolt which can be used in practical engineering was presented in this paper. Then, the stress and failure mode of this bolt were discussed, and the theoretical equation of the bearing capacity was derived by using the elastic-plastic theory. In addition, the assembly and fabrication technology of this bolt in practical foundation pit engineering was described in detail. Finally, the field pull-out test of the polycystic aeration bolt was carried out, and the test results were compared with those of the conventional grouting bolt, which indicated that this new bolt has a greater advantage in bearing capacity than the conventional grouting bolt, verifying the feasibility of the structural design scheme of the polycystic aeration bolt proposed in this paper.

scholarly journals Study on Flexural Bearing Capacity Calculation Method of Enclosure Pile with Partial Excision in Deep Foundation Pit

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Mingfeng Lei ◽  
Linghui Liu ◽  
Yuexiang Lin ◽  
Jin Li
Keyword(s):  
Flexural Strength ◽  
Bearing Capacity ◽  
Calculation Method ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Theoretical Derivation ◽  
Deep Foundation Pit ◽  
Practical Engineering ◽  
Capacity Calculation ◽  
Partial Excision

During deep foundation pit construction, the structural clearance intrusion, which is caused by the complex formation conditions and the inefficient drilling equipment, is usually detected due to the vertical deviation of piles. To meet construction requirements, pile parts intruding into the structural clearance are supposed to be excised. However, the sectional flexural strength of the pile is bound to decrease with partial excision, which would reduce the bearing capacity of the enclosing structure during construction. In this paper, a theoretical derivation of the normal sectional flexural strength of the partially excised circular pile is proposed. The derivation adopts the assumption of the plane section and steel ring equivalence and can be solved by the bisection method. Furthermore, the calculation method is applied to the pile evaluation of a practical engineering; also, the method is verified by the numerical method. The application results show that the excision of rebar and pile’s sectional area will cause a rapid linear decline in the sectional flexural strength. After excising 18 cm radial thickness of the circular pile (ϕ800 mm) and 6 longitudinal rebars, the sectional flexural strength of the pile decreases to 58% from the origin, which cannot meet the support requirement. The analysis indicates that pile reinforcements must be carried out to maintain the construction safety.

scholarly journals Hysteretic Behavior of Beam-to-Column Joints with Cast Steel Connectors

2019 ◽  
Vol 2019 ◽  
pp. 1-20
Author(s):  
Guofeng Xue ◽  
Wei Bao ◽  
Jin Jiang ◽  
Yongsong Shao
Keyword(s):  
Energy Dissipation ◽  
Bearing Capacity ◽  
Cast Steel ◽  
Hysteretic Behavior ◽  
Element Analysis ◽  
Rapid Repair ◽  
Practical Engineering ◽  
New Type ◽  
Column Joint ◽  
Energy Dissipation Capacity

This study proposed a beam-to-column joint equipped with a new type of cast steel connector. The cast steel connector concentrated the primary portion of the deformation and energy dissipation of the joint and was installed with full bolted connections, rendering it a replaceable energy dissipation component and facilitating the rapid repair of the joint after an earthquake. Three full-scale specimens were fabricated and tested to investigate the hysteretic behaviors of the proposed joints under cyclic loadings. The results showed that the proposed cast steel connector exhibited reliable ductility and energy dissipation capacity. The beam-to-column joints with cast steel connectors under appropriate configuration can limit the deformation to the cast steel connector and protect the remaining joint components from plastic deformation. A more detailed finite element analysis was performed to investigate the hysteretic behavior of the joint further. The FEM results illustrated that the thickness of the vertical leg of the cast steel connector can significantly influence the stiffness and bearing capacity of the joint. Meantime, it would improve the hysteretic behavior effectively. The proposed beam-to-column joints with cast steel connectors can achieve the requirement of stiffness and load-bearing capacity and can be widely applicable in practical engineering.

scholarly journals Development of a New Inflatable Controlled Anchor System and Experimental Study of pull-out Capacity

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Xuexiang Yang ◽  
Shanpo Jia ◽  
Caoxuan Wen ◽  
Yuanjie Liu
Keyword(s):  
Bearing Capacity ◽  
Field Tests ◽  
Ultimate Bearing Capacity ◽  
Inflation Pressure ◽  
Working Mechanism ◽  
Anchor System ◽  
System A ◽  
Pull Out ◽  
New Type ◽  
Soil Interface

Considering the deficiency of traditional anchors, we propose a new type of inflatable controlled anchor system in this paper. The working mechanism and its structural composition of newly designed inflatable controlled device are discussed in detail. To investigate the performance and pull-out capacity of this new anchor system, a series of field tests were carried out under different inflation pressure conditions. By comparing these test results with those of traditional grouting anchors, a full-process constitutive model of anchor-soil interface is proposed to depict the pull-out characteristics of the inflatable controlled anchor. The results show that the ultimate bearing capacity of the inflatable controlled anchor is greater than that of the traditional grouting anchor when the inflation pressure is greater than 0.2 MPa and the ultimate bearing capacity of this new anchor improves obviously with the increase of inflation pressure. When the inflation pressure reaches 0.4 MPa, the ultimate bearing capacity of the inflatable controlled anchor is 2.08 times that of the traditional grouting anchor. Through comparison with the experimental curves, the results of model calculation indicate that the proposed anchor-soil interface constitutive equation can describe the pull-out characteristics of the inflatable controlled anchor. The designed controlled anchor has the advantages of no grouting, recyclability, rapid formation of anchoring force, and adjustable anchoring force.

A Discussion of the Stability of Foundation Pit or Slope with Soft Interlayer or with Back Berm

2014 ◽  
Vol 1065-1069 ◽  
pp. 96-99
Author(s):  
Hai Ying Hu ◽  
Xiao Wen Zhou ◽  
Zhi Xing Huang
Keyword(s):  
Bearing Capacity ◽  
Soft Soil ◽  
High Water ◽  
High Water Content ◽  
Sliding Surface ◽  
Foundation Pit ◽  
Soft Interlayer ◽  
The Difference ◽  
The Stability ◽  
Slice Method

The soft soil in Pearl River Delta regions is characterized with high water content, high compressibility and low bearing capacity. Therefore, when building the structures on such foundation, it’s necessary to pay attention to the deformation and stability. The projects' practice shows that, when analyzing the stability on foundation pit or slope with soft interlayer, it should not only calculate the overall stability of the slope, but also calculate the stability or bearing capacity of the foundation. Although sometimes the stability of the slope meets the requirements, it doesn’t means that the bearing capacity of the foundation meets the requirements because of the existence soft interlayer, the limitations of the circle slice method and the difference between the sliding surface and the actual sliding surface.

Studies on the Efficiency of the CFG Pile-Net Reinforcement in the Soft Soil Subgrade

2011 ◽  
Vol 94-96 ◽  
pp. 2222-2225
Author(s):  
Feng Zhang ◽  
Zhao Yi Xu ◽  
Zhi Yi Li
Keyword(s):  
Bearing Capacity ◽  
Test Section ◽  
Soft Soil ◽  
Quality Detection ◽  
Detection Technology ◽  
Practical Engineering ◽  
And Control ◽  
Cfg Pile

Combined with Wuhan test section of Wuhan-Guangzhou passenger special line, proportioning of mixtures、integrity of pile、bearing capacity and cushion of CFG pile detection technology were studied in this paper. The systematic and perfect methods of quality detection and control standard have been put forward. It provide useful reference for practical engineering．

scholarly journals Model Test Ultimate Bearing Capacity of Bakau Piles Foundation on Soft Soil Deposit

2018 ◽  
Vol 1 (2) ◽  
pp. 94-99
Author(s):  
Muhammad O Yunus
Keyword(s):  
Bearing Capacity ◽  
Pile Foundation ◽  
Soft Soil ◽  
Ultimate Bearing Capacity ◽  
Small Scale ◽  
Test Results ◽  
Loading Test ◽  
Deep Foundation ◽  
Foundation Model ◽  
Ultimate Settlement

The pile foundation is one of the deep foundation types commonly used to support building loads when hard soil layers are deeply located. To determine the ultimate bearing capacity of a pile foundation of the load test results, there are several methods commonly used to interpretation test results such as Davisson method, Mazurkiewich method, Chin method, Buttler Hoy method and De Beer method. The aim of this study was to determine the characteristics of soft soil and bakau piles used in the study and to analyze the size of the bearing capacity ultimate of pile foundation that is modeled on a small scale in the laboratory. From the test results of material characteristics of the soil used is organic clay type with medium plasticity with specific gravity 2.75, liquid limit, LL = 50.36% and plasticity index, PI = 13.2%. While the results of testing the characteristics of bakau piles obtained average water content of 21.58%, tensile strength of 18.51 MPa, compressive strength of parallel fiber 23.75 MPa and perpendicular fiber 14.10 MPa, bending strength 106, 22 MPa, and strong split 29.91 MPa. From the result of loading test of the foundation model in the laboratory, it is found that the ultimate bearing capacity of the model without foundation is 41.00 kN with the ultimate settlement of 14.00 mm, the model of the 20 cm long bakau piles foundation is 52.00 kN with the ultimate settlement of 13.00 mm, the foundation model a 30 cm long bakau piles foundation of 54.00 kN with a 10.00 mm ultimate settlement, a 40 cm long bakau piles foundation model of 56.00 kN with an ultimate settlement of 8.50 mm.

Model Test for Fatigue Performance on New Type Solid Round Rigid Suspender for a High-Speed Railway Bridge

2011 ◽  
Vol 368-373 ◽  
pp. 94-99
Author(s):  
Jin Gang Zhao ◽  
Ren Da Zhao ◽  
Yu Lin Zhan
Keyword(s):  
Bearing Capacity ◽  
Model Test ◽  
High Speed ◽  
Stress Amplitude ◽  
Fatigue Performance ◽  
Plastic State ◽  
Test Results ◽  
Railway Bridge ◽  
High Speed Railway ◽  
New Type

This paper presents a study on the fatigue performance of a new type solid round rigid suspender in a high-speed railway bridge. The relevant information about the model design, manufacture, loading procedure and test scheme is presented. The model test results show that the maximum axial stress amplitude are less than the allowable fatigue stress amplitude for most of the measuring points, and no crack occurs on the short and the long suspender models’ body and connection structural detail after 2 million fatigue cycles, the fatigue performance meets the requirement. The bearing capacity test results after fatigue test show that the short and the long suspender models entering plastic state and without fracture under 131% and 119% of the test load. The suspenders’ bearing capacity meets the design requirement. This fatigue model test study shows that the design of the new type solid round rigid suspender is reasonable and safe.

Analyses of Earth Pressure on Gridding Concrete Retaining Wall in the Excavation of Deep Foundation Pit in Soft Soil Area

2011 ◽  
Vol 52-54 ◽  
pp. 2181-2186
Author(s):  
Guang Zhu Zhou ◽  
Xu Wei ◽  
Chen Yu
Keyword(s):  
Retaining Wall ◽  
Soft Soil ◽  
Earth Pressure ◽  
Front Wall ◽  
Three Dimension ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Finite Element Software ◽  
The Earth ◽  
Practical Engineering

This paper is mainly to study earth pressure on Gcrw used as a new kind of supporting structures in the excavation of deep foundation pits in soft soil region. On the basis of the simulation of step by step excavation by using big finite element software Abaqus/CAE and considering three-dimension elastoplastic stress state, the characteristics of different earth pressure are systematically discussed upon practical engineering. By comparing simulation results with calculated results based on calculation formula of Rankine Theory, it can be seen that the earth pressure in active zone is different from theoretic active earth pressure and earth pressure at rest while walls and soil in the gridding are regarded as a whole, which is greater than the former and somewhere similar to the latter, the earth pressure in passive zone is bigger than theoretic value of passive earth pressure, it is the tensive force from partition wall that prevent the front wall from overturning. These conclusions will be helpful for design and construction of new retaining wall.

scholarly journals Uplift Behavior of Belled Short Piles in Weathered Sandstone

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Bai Yang ◽  
Jianlin Ma ◽  
Wenlong Chen ◽  
Yanxin Yang
Keyword(s):  
Shear Strength ◽  
Bearing Capacity ◽  
Calculation Model ◽  
Uplift Capacity ◽  
Test Results ◽  
Loading Test ◽  
Pull Out ◽  
Initial Stage ◽  
Uplift Load ◽  
Double Circuit Line

Field pull out test results of 500 kV double-circuit line of Luping-Fule are presented in this paper to investigate the uplift bearing behavior of rock-socketed belled short piles. A calculation model of rock-socketed belled short pile has been proposed. During the initial stage of loading test, uplift load is shared by even section and bell of the pile, and the bell continues to bear uplift load after the lateral resistance of even section pile reaches the limit. A different performance has been found on the case of long belled pile. At the ultimate state, the uplift resistance provided by bell accounts for about 54.9% and 34.7% of the total uplift capacity for the 6.0 m long and 7.0 m long piles, respectively. Increasing pile length has been found to noticeably increase the ultimate uplift bearing capacity, while it has less effect on the displacement of pile top. The uplift capacity of even section pile is associated with the shear strength of rock mass around the pile, and the test results demonstrate that the ultimate resistance can be equal to the shear strength. The calculation method proposed in this paper is proven to be able to accurately predict the ultimate uplift bearing capacity of the rock-socketed belled short piles.

Sign in / Sign up

Export Citation Format

Share Document