Model Tests of Foundation Bearing Capacity of Sandy Soil and Pile Foundation Bearing Capacity

2014 ◽  
Vol 580-583 ◽  
pp. 113-117
Author(s):  
Shi Jie Lu ◽  
Hua Dong Chen ◽  
Wei Chen ◽  
Tong Xiang ◽  
Xie Feng Hong

Using self―made model device, researchers studied the characteristics of foundation settlement of sandy soil and pile foundation load―bearing in sandy soil. Through weight loading, researchers analyzed the phenomenon of foundation settlement. Then, researchers embedded friction piles in sand, so as to analyzed pile foundation bearing capacity. The methods and results of the research can provide guidance for teaching of Soil mechanics and foundation engineering.

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Tianzhong Ma ◽  
Yanpeng Zhu ◽  
Xiaohui Yang ◽  
Yongqiang Ling

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.


2013 ◽  
Vol 438-439 ◽  
pp. 1414-1418
Author(s):  
Wei Ding ◽  
Qing Liu ◽  
Bing Yu Wang ◽  
Kang Kang Sun ◽  
Feng Tao Sui

This paper determines the bearing capacity of pile and shaft resistance by the curve match method of high strain dynamic testing. By the comparison of bearing capacity of pile between the testing results of static loading and dynamic high strain, the reliability and surveying precision of the curve match method is analyzed, and the error sources and reasons are explored, to reasonably determine the design parameters of pile foundation engineering.


Author(s):  
Amelia Wijaya ◽  
Aksan Kawanda

<span><em>The foundation of the raft post is the bottom structure of a building that channeled the load from the structure </em><span><em>over the soil under it. Carrying capacity of drill pile foundation is influenced by the capacity of the pole tip</em><br /><span><em>and bearing capacity of the pole blanket. The decline in this area can be an immediate decline and a </em><span><em>decrease in consolidation. This study aims to analyze the decrease of raft poles and the proportion of load </em><span><em>bearing in the bogie area of the Kelapa Gading LRT warehouse depot - Jakarta. From the analysis of the</em><br /><span><em>NSPT test results in the field, the ultimate carrying capacity and the decrease that occurred on the raft poles </em><span><em>were obtained. Based on the results of calculation of the ultimate carrying capacity of a single drill pole of </em><span><em>1.1 x 104 kN and the carrying capacity of the group is 1.1 x 108 kN. Calculation of group efficiency with the </em><span><em>Feld method is obtained at a value of 0.588. In the calculation of the immediate decline of the pole, a value of </em><span><em>5 cm is obtained and a decrease in consolidation of 7 cm. From the calculation of the proportion of raft pole</em><br /><span><em>load bearing the value of Pr = 6 x 10-6 is obtained, which means that load bearing can be said to be </em><span><em>dominated by rafts.</em></span></span></span></span></span></span></span></span></span></span></span><br /><br class="Apple-interchange-newline" /></span>


2008 ◽  
Vol 24 (3) ◽  
pp. 285-296 ◽  
Author(s):  
J.-C. Chang ◽  
J.-J. Liao ◽  
Y.-W. Pan

AbstractThis paper aims to investigate the failure mechanism of a shallow foundation on poorly cemented sandstone and to propose an upper bound solution for the bearing capacity of the foundation. A series of laboratory material and load-bearing model tests with specimens made of artificial rock mimic undisturbed natural poorly cemented sandstone.Based on a series of load-bearing model tests, bearing behavior and progressive failure mechanisms are investigated. It was found that the bearing behavior on poorly cemented sandstone is distinct from the cases on hard rock or on soil, and exhibits both plasticity and brittle characteristics. It is noted that the bearing capacity formulas for a shallow foundation commonly used for soil or hard rock are not appropriate for the case of poorly cemented soft sandstone. Based on the observed failure mechanism, a simplified plastic collapse mechanism is proposed and an upper-bound solution on the basis of a multi-block translation mechanism is formulated. It is shown that the upper bound solution agrees well with the experimental bearing capacity as long as a proper non-associated flow rule is adopted.


2014 ◽  
Vol 501-504 ◽  
pp. 234-237
Author(s):  
Yan Peng Zhu ◽  
Ze Xue Bao ◽  
Tian Zhong Ma ◽  
Chun Jing Lai

The application of pile foundation is promoted by the rapid development of the high speed railway, highway, high-rise buildings and big volume weight of building. However, the static load test and low strain test play a very important role in pile foundation inspection and ensurement of the quality of pile foundation engineering. In this paper, combined with the engineering of the basis of a hospital in lanhou, the author analyzed the results of 7 test piles static load test and a large number of low strain test and summarised pile testing contents and methods. At the same time,the bearing capacity of anchor pile in static load test is discussed.


2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Hui Yuan ◽  
Xiaohong Bai ◽  
Hehui Zhao ◽  
Jingren Wang

Geogrids are widely used in foundation engineering for reinforcing foundations due to their light weight, high strength, and excellent performance. In this study, two kinds of polypropylene biaxial geogrids were used, and indoor thermal oxygen and photooxygen aging tests were carried out. The residual mechanical stability of the exposed materials was determined by tensile testing. The results of both accelerated test methods are discussed and compared in detail. After aging of the geogrid, the trend of tensile strength and fracture elongation change with aging time is obtained. The gray prediction model was used to predict the variation in the retention rate of tensile strength in the geogrid with photooxygen aging time. Model tests of cushions were carried out in a large geogroove to compare the load bearing characteristics of pure sand and the unaged and aged geogrid-reinforced sand cushions. The results show that ultraviolet radiation illuminance plays a decisive role in the aging degree of the polypropylene geogrid. The influence of photooxygen aging on the tensile strength and fracture elongation of a polypropylene biaxial geogrid is greater than that of thermal oxygen aging. Different types of polypropylene biaxial geogrids with photooxygen aging showed different retention rates of tensile strength, and the aging resistance of the geogrid with higher tensile strength was significantly higher than that of the geogrid with lower tensile strength. The tensile strength of the geogrid has an effect on the bearing capacity of reinforced sand cushions. Under proper elongation, the bearing capacity of the reinforced sand cushion is clearly improved compared with that of the unreinforced cushion. The aging behavior of the two geogrids reduces the load bearing capacity of the reinforced cushion by influencing the property of the interface between the geogrid and sand.


2013 ◽  
Vol 35 (1) ◽  
pp. 233-244
Author(s):  
Michał Suska ◽  
Wojciech Puła

Abstract HDMR (High Dimensional Model Representation) is a relatively new method that is used to form response surface based on results obtained through laboratory experiments or through numerical calculations. So far the method has been used mainly in chemistry, although a few studies conducted in recent years show that it can be considered a useful tool in soil mechanics and foundation engineering. The subject matter of this paper is the application of HDMR method to reliability assessment of bearing capacity of layered soils. Madej’s method, widely recognized and used by Polish engineers, is applied to conduct the calculations. In the analysed case bearing capacity is not expressed by means of an explicit formula. To fit the approximate functions of bearing capacity, its values are calculated on a grid of points equally spread on ranges of variables. Finding the relation between input and output data is conducted by means of assessing each variable’s influence on response’s mean value within a given scope. Approximate functions have been used to calculate reliability indices by means of FORM, SORM and Monte Carlo methods.


2021 ◽  
Vol 274 ◽  
pp. 03020
Author(s):  
Ilisar Mirsayapov ◽  
Ildus Shakirov ◽  
Daniya Nurieva

During the building reconstruction with floors addition, there is a need to evaluate the building frame and foundation soil bearing capacity, especially if there are deviations from the design parameters. As a result of the field and numerical studies, we determined the basic change patterns in the stress-strain state of the 12-storey building load-bearing structures with a monolithic reinforced concrete frame due to uneven pile foundation deformation. We also found the influence degree of the existing deviations from the design parameters to the structures bearing capacity. The research results can be applied in reconstruction conditions with a significant increase in the load on the existing load-bearing elements of the building and on the pile foundation.


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