scholarly journals Settlement and bearingcapacity of long pile

Vestnik MGSU ◽  
2015 ◽  
pp. 52-61
Author(s):  
Armen Zavenovich Ter-Martirosyan ◽  
Zaven Grigor’evich Ter-Martirosyan ◽  
Tuan Viet Trinh ◽  
Ivan Nikolaevich Luzin
Keyword(s):  
Analytical Solution ◽  
Bearing Capacity ◽  
Quantitative Estimation ◽  
Pile Head ◽  
Dead Load ◽  
Rigid Pile ◽  
Side Face ◽  
Pile Settlement ◽  
General Force ◽  
Surrounding Soil

When a long pile is interacting with the soil, the combined force applied to the pile head is distributed among the side face and the pile toe inhomogeneously. The toe gets not more than 30 % from the general force, which doesn’t let using the reserves of the bearing capacity of relatively firm soil under the fifth pile. Account for the depth of the pile toe and the dead load of the soil allows increasing the bearing capacity of the soil under the pile toe and decrease the pile settlement in general. For the quantitative estimation of these factors it is necessary to solve the task on the interaction of the rigid long pile with the surrounding soil, which includes under the pile toe, which is absolutely rigid round stamp.The article presents the formulation and analytical solution to a quantification of the settlement of a circular foundation with the due account for its depth, basing on the development of P. Mindlin’s studies as well as the interactions between a long rigid pile and surrounding soils, including under pile toe.It is proposed to compare the estimated value of stresses under the heel of pile with the initial critical load for the round foundation to check the condition that the estinated value is less than the intial critical one.

The Ultimate Shear Bearing Capacity of RC Beam Strengthened with SWR External Prestressing under Dead Load Level when Strengthening

2011 ◽  
Vol 368-373 ◽  
pp. 2175-2179
Author(s):  
Tian Lai Yu ◽  
Hong Kun Han ◽  
Xin Yu Li ◽  
Qiang Ma
Keyword(s):  
Bearing Capacity ◽  
Concrete Beams ◽  
Steel Wire ◽  
Load Level ◽  
Shear Capacity ◽  
Dead Load ◽  
External Prestressing ◽  
Reduction Coefficient ◽  
Shear Bearing Capacity ◽  
The Dead

The shear resistant with SWR (steel wire rope) external prestressing is a kind of new type of reinforcement technique. The advantages of the method are ideal reinforcement effect, durability, and convenient construction. So the method has been paid attention by more and more scientists and technical workers. Through the experiment of 1 basic beam and 3 strengthened beams which are in different dead load levels, the influence of damage degree of original beams and the dead load level of strengthened beams are analyzed. The reduction coefficient values of shear capacity under different dead load level are researched. The research is shown that: with the dead load level increasing, the improve degree of shear capacity of strengthened concrete beams is smaller. The mathematical model is established, which is about dead load level and reduction coefficient of shear capacity of strengthened concrete beams. The result is to take 0.75 as the reduction coefficient of shear capacity. The value is reasonable in calculating the shear bearing capacity of strengthened beams under dead load.

scholarly journals Simplified analytical solution for stress concentration ratio of piled embankments incorporating pile–soil interaction

2021 ◽  
Author(s):  
Qiang Luo ◽  
Ming Wei ◽  
Qingyuan Lu ◽  
Tengfei Wang
Keyword(s):  
Stress Concentration ◽  
Analytical Solution ◽  
High Speed ◽  
Concentration Ratio ◽  
Differential Settlement ◽  
Fundamental Parameter ◽  
Soil System ◽  
Rigid Pile ◽  
Stress Concentration Ratio ◽  
Piled Embankments

AbstractPiled embankments have been extensively used for high-speed rail over soft soils because of their effectiveness in minimizing differential settlement and shortening the construction period. Stress concentration ratio, defined as the ratio of vertical stress carried by pile heads (or pile caps if applicable) to that by adjacent soils, is a fundamental parameter in the design of piled embankments. In view of the complicated load transfer mechanism in the framework of embankment system, this paper presents a simplified analytical solution for the stress concentration ratio of rigid pile-supported embankments. In the derivation, the effects of cushion stiffness, pile–soil interaction, and pile penetration behavior are considered and examined. A modified linearly elastic-perfectly plastic model was used to analyze the mechanical response of a rigid pile–soil system. The analytical model was verified against field data and the results of numerical simulations from the literature. According to the proposed method, the skin friction distribution, pile–soil relative displacement, location of neural point, and differential settlement between the pile head (or cap) and adjacent soils can be determined. This work serves as a fast algorithm for initial and reasonable approximation of stress concentration ratio on the design aspects of piled embankments.

scholarly journals INTERACTION OF A LONG PILE OF FINITE STIFFNESS WITH SURROUNDING SOIL AND FOUNDATION CAP

Vestnik MGSU ◽  
2015 ◽  
pp. 72-83
Author(s):  
Armen Zavenovich Ter-Martirosyan ◽  
Zaven Grigor’evich Ter-Martirosyan ◽  
Tuan Viet Trinh
Keyword(s):  
Differential Equation ◽  
Analytical Solution ◽  
Carrying Capacity ◽  
Strain State ◽  
Order Differential Equation ◽  
Deformation Modulus ◽  
First Case ◽  
Equivalent Modulus ◽  
Underlying Soil ◽  
Surrounding Soil

The article presents the formulation and analytical solution to a quantification of stress strain state of a two-layer soil cylinder enclosing a long pile, interacting with the cap. The solution of the problem is considered for two cases: with and without account for the settlement of the heel and the underlying soil. In the first case, the article is offering equations for determining the stresses of pile’s body and the surrounding soil according to their hardness and the ratio of radiuses of the pile and the surrounding soil cylinder, as well as formulating for determining equivalent deformation modulus of the system “cap-pile-surrounding soil” (the system). Assessing the carrying capacity of the soil under pile’s heel is of great necessity. In the second case, the article is solving a second-order differential equation. We gave the formulas for determining the stresses of the pile at its top and heel, as well as the variation of stresses along the pile’s body. The article is also formulating for determining the settlement of the foundation cap and equivalent deformation modulus of the system. It is shown that, pushing the pile into underlying layer results in the reducing of equivalent modulus of the system.

Study of Fire Behavior of a Profiled Sheet-Ceramsite Concrete Composite Floor

2011 ◽  
Vol 243-249 ◽  
pp. 5231-5235
Author(s):  
Xin Tang Wang ◽  
Ming Zhou ◽  
Hai Jiang Wang ◽  
Zhi Guo Xie
Keyword(s):  
Bearing Capacity ◽  
Fire Behavior ◽  
Experimental Results ◽  
Dead Load ◽  
Fire Response ◽  
Fire Load ◽  
Distributed Load ◽  
Obvious Change ◽  
Bending Capacity

In order to study the fire behavior of the profiled sheet-ceramsite concrete composite floor subjected to fire load, research on fire response and post-fire bearing capacity of a profiled sheet-ceramsite concrete composite floor subjected to dead load, which has no shearing nails, is carried out here through experiment. Based on the experimental results, the fire behavior and post-fire bearing capacity of the floor after exposure to fire are analyzed. It is shown that the failure form of the profiled sheet-ceramsite concrete composite floor after exposure to fire has obvious change compared with the floor not subjected to fire load, but the composite floor subjected to fire still exhibits higher bending capacity, and the ultimate value of the equivalent distributed load is up to 35kN/m2, which may be used as basis of strengthening and repairing of the profiled sheet-ceramsite concrete composite floor after exposure to fire.

scholarly journals Pile Model Tests Using Strain Gauge Technology

2015 ◽  
Vol 37 (3) ◽  
pp. 49-52 ◽  
Author(s):  
Adam Krasiński ◽  
Tomasz Kusio
Keyword(s):  
Bearing Capacity ◽  
Axial Force ◽  
Strain Gauge ◽  
Force Measurement ◽  
Ground Level ◽  
Model Tests ◽  
Scale Model ◽  
Small Scale ◽  
Pile Head ◽  
Pile Model

Abstract Ordinary pile bearing capacity tests are usually carried out to determine the relationship between load and displacement of pile head. The measurement system required in such tests consists of force transducer and three or four displacement gauges. The whole system is installed at the pile head above the ground level. This approach, however, does not give us complete information about the pile-soil interaction. We can only determine the total bearing capacity of the pile, without the knowledge of its distribution into the shaft and base resistances. Much more information can be obtained by carrying out a test of instrumented pile equipped with a system for measuring the distribution of axial force along its core. In the case of pile model tests the use of such measurement is difficult due to small scale of the model. To find a suitable solution for axial force measurement, which could be applied to small scale model piles, we had to take into account the following requirements: - a linear and stable relationship between measured and physical values, - the force measurement accuracy of about 0.1 kN, - the range of measured forces up to 30 kN, - resistance of measuring gauges against aggressive counteraction of concrete mortar and against moisture, - insensitivity to pile bending, - economical factor. These requirements can be fulfilled by strain gauge sensors if an appropriate methodology is used for test preparation (Hoffmann [1]). In this paper, we focus on some aspects of the application of strain gauge sensors for model pile tests. The efficiency of the method is proved on the examples of static load tests carried out on SDP model piles acting as single piles and in a group.

scholarly journals Bearing Characteristics of Composite Pile Group Foundations with Long and Short Piles under Lateral Loading in Loess Areas

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Tianzhong Ma ◽  
Yanpeng Zhu ◽  
Xiaohui Yang ◽  
Yongqiang Ling
Keyword(s):  
Bearing Capacity ◽  
Pile Foundation ◽  
Horizontal Displacement ◽  
Pile Group ◽  
Lateral Load ◽  
Test Model ◽  
Pile Head ◽  
Load Bearing ◽  
Composite Pile ◽  
Pile Length

It is very necessary to research the bearing characteristics of composite pile group foundations with long and short piles under lateral load in loess areas, because these foundations are used widely. But few people researched this problem in loess areas up to now worldwide. In this paper, firstly, an indoor test model of a composite pile foundation with long and short piles is designed and then employed to explore the vertical load bearing characteristics and load transfer mechanisms of a single pile, a four-pile group, and a nine-pile group under different lateral loads. Secondly, ANSYS software is employed to analyze the load-bearing characteristics of the test model, and for comparison with the experimental results. The results demonstrate the following. (1) The lateral force versus pile head displacement curves of the pile foundation exhibit an obvious steep drop in section, which is a typical feature of piercing damage. A horizontal displacement limit of the pile foundation is 10 mm and 6mm for the ones sensitive to horizontal displacement. (2) The axial force along a pile and frictional resistance do not coincide, due to significant variations and discontinuities in the collapsibility of loess; a pile body exhibits multiple neutral points. Therefore, composite pile groups including both long and short piles could potentially maximize the bearing capacity and reduce pile settlement. (3) The distribution of stress and strain along the pile length is mainly concentrated from the pile head to a depth of about 1/3 of the pile length. If the lateral load is too large, short piles undergo rotation about their longitudinal axis and long piles undergo flexural deformation. Therefore, the lateral bearing capacity mainly relies on the strength of the soil at the interface with the pile or the horizontal displacement of the pile head.

Study on Longitudinal Vibration of Pile in the Viscous Damping Layered Soils

2010 ◽  
Vol 168-170 ◽  
pp. 2450-2457
Author(s):  
Yin Hui Wang ◽  
Kui Hua Wang ◽  
Zhi Xiang Zha ◽  
Ren Bo Que
Keyword(s):  
Analytical Solution ◽  
Frequency Domain ◽  
Time Domain ◽  
Longitudinal Vibration ◽  
Exciting Force ◽  
Viscous Damping ◽  
Layered Soils ◽  
Pile Head ◽  
Wave Effect ◽  
Velocity Response

Taking axisymmetric wave effect of soil into account, longitudinal vibration of pile in viscous damping layered soils undergoing arbitrary load is theoretically investigated. An analytical solution for admittance at the level of the pile head in frequency domain is yielded. So is a semi-analytical solution for velocity response in time-domain subjected to a semi-sine exciting force. Based on the solutions proposed herein, the effects of variety of soil modulus on admittance curves and reflection wave curves are emphatically discussed. The conclusions can provide theoretical guidance for non-destruction test of piles.

Research on Fire Behaviour of a Lightweight Aggregate Concrete Composite Floor

2011 ◽  
Vol 368-373 ◽  
pp. 911-914
Author(s):  
Hong Liang Sun ◽  
Xin Tang Wang ◽  
Ping Xin Sun
Keyword(s):  
Bearing Capacity ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Fire Performance ◽  
Fire Behaviour ◽  
Dead Load ◽  
Fire Response ◽  
Fire Load ◽  
Aggregate Concrete ◽  
Bending Capacity

To study the fire performance of the profiled sheet-light aggregate concrete composite floor subjected to fire load, study of fire response and post-fire bearing capacity of a profiled sheet-lightweight aggregate concrete composite floor subjected to dead load is carried out. Based on the experimental results, the fire performance and post-fire bearing capacity of the floor after exposure to fire are analyzed. It is shown that the failure form of the profiled sheet-ceramsite concrete composite floor after exposure to fire still exhibits higher bending capacity, and the ultimate value of the equivalent distributed load is up to 30.69kN/m2, which may be used as basis of strengthening and repairing of the profiled sheet-ceramsite concrete composite floor after exposure to fire.

Experiment Research on Bored Pile with Post-Grouting Technology

2013 ◽  
Vol 838-841 ◽  
pp. 854-857
Author(s):  
Rui Chao Cheng ◽  
Xin Yu
Keyword(s):  
Bearing Capacity ◽  
Static Load ◽  
Load Test ◽  
Static Load Test ◽  
Pile Head ◽  
Experiment Research ◽  
Friction Resistance ◽  
Bored Pile ◽  
Post Grouting ◽  
Side Friction

The bearing capacity characteristics and side friction characters of post-grouting pile were studied in the static load test which included two piles with post-grouting or not. When the pile head settlements were same, the loads applied on the pile top were used to analyze the bearing properties of post-grouting pile. We got the ultimate side friction of post-grouting pile after fitting test curves of relations between friction resistance and displacement. The tests indicate that both the bearing capacity characteristics and side friction of post-grouting pile are increased in various degrees.

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