scholarly journals Experimental Study on Static Load of Large-Diameter Piles in Nonuniform Gravel Soil

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Baoyun Zhao ◽  
Xiaoping Wang ◽  
Mijia Yang ◽  
Dongyan Liu ◽  
DongSheng Liu ◽  
...  

With the development of tourism, the number of multistorey buildings in mountain areas is increasing gradually, and the requirements of the form and bearing capacity of foundation in landslide areas are getting more demanding than ever. In-situ testing of rock and soil mass in slope area has important practical significance for improving the stability of building foundation. Taking a project in Baishi Mountain located in southwest of China as an example, firstly, the geological structure and mechanical properties of soil are analyzed. Then, two types of pile foundations, i.e., empty-bottom pile foundations and solid-bottom pile foundations, are designed based on the characteristics of the geological structure for carrying out the static load test on pile foundation. The test results are as follows: (a) the load settlement curve (Q-S) of the empty-bottom test pile shows a steep drop, while the Q-S curve of the solid-bottom test pile shows a gradual change, showing that the end-bearing friction pile’s property and the ultimate bearing capacity of the solid-bottom pile are higher than those of the empty-bottom pile. (b) The maximum lateral friction of the four test piles is 139.158 kPa, 148.015 kPa, 150.828 kPa, and 154.956 kPa, respectively. (c) The shaft skin resistance under ultimate load is coming close to the maximum value, and the maximum values are 9.792 mm, 7.939 mm, 9.881 mm, and 14.97 mm, respectively. Research results can serve as design bases for the pile foundation of multistorey buildings located in landslide areas of Baishi Mountain in the southwest of China and also as references for the engineering application of pile foundation in similar geological fracture areas.

2014 ◽  
Vol 638-640 ◽  
pp. 671-674
Author(s):  
Yu Zhou Sima ◽  
Qing Hua Sun

In static load test, most of piles do not destroy, the piles still exist capacity, which reduce the reliability index of pile foundation. This paper employs Bayesian Statistic method to update the measured capacity of piles. Meanwhile, based on updating data, the reliability index is calculated considering the destruction of piles. The case study shows that the reliability index of capacity becomes large when the time of pile destruction increases. Therefore, when judging the safety of pile foundation, it is highly necessary to consider the influence of pile destruction on reliability of piles.


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.


2000 ◽  
Vol 37 (6) ◽  
pp. 1283-1294 ◽  
Author(s):  
Caizhao Zhan ◽  
Jian-Hua Yin

The Mass Transit Railway Corporation proposes to construct the Tseung Kwan O Depot (TKD) within Area 86 reclamation at Tseung Kwan O as part of the Tseung Kwan O Extension. The proposed foundation for the TKD comprises about 1000 large-diameter, bored, cast in situ, drilled shafts founded on or socketed into rock. To confirm the design allowable end bearing capacity and rock socket side resistance for the drilled shaft foundations, two test piles were constructed and tested. Both test piles were instrumented with strain gauges and rod extensometers. This paper presents the static compressive load test results on both test piles. The test results indicate that an end bearing capacity of 20.8 MPa (design allowable 7.5 MPa) and rock socket side resistance 2.63 MPa (design allowable 0.75 MPa) are achieved during the pile load tests with no sign of failure.Key words: drilled shaft, static load test, end bearing capacity, rock socket, rock socket side resistance, load transfer.


2014 ◽  
Vol 578-579 ◽  
pp. 663-666
Author(s):  
Qi Hong Wu ◽  
Qing Xu ◽  
Shi Ming Wan

Firstly, the technology of screw pile is introduced briefly. It has high body quality, high bearing capacity and wide application prospect. Then, based on engineering examples, the results of static load test and high strain testing for the bearing capacity of SCREW PILE foundation are analyzed contrastively. The bearing capacity value tested by high strain dynamic testing is higher than the static loading test’s with 13%~21%, which should be attached importance in the check and accept and application of the screwed pile. The analysis and sum up of testing results should be considered to the design and application of screwed pile, providing some reference to the quality judge and bearing capacity confirming is another purpose in the paper.


2011 ◽  
Vol 250-253 ◽  
pp. 2271-2275
Author(s):  
Cheng Wang ◽  
Qi Zhang

Vertical static load test is widely used in the determination of pile bearing capacity, the mathematical model used to fit test pile data in determining the bearing capacity is essential. From the perspective of analytic geometry, the paper analyzes the traditional method of hyperbola, of which the asymptotic line of equilateral hyperbola was used to determine the ultimate bearing capacity. By extending the equal-axed conditions, a more general form of hyperbolic equation is derived and feasibility of such method is also analyzed, which indicates that the maximum point of curvature in such hyperbolic curve can determine the ultimate bearing capacity and such method is proved to be reasonable in practical projects.


2018 ◽  
Vol 195 ◽  
pp. 03005
Author(s):  
Ferry Fatnanta ◽  
Andarsin Ongko

Peat is a kind of soil with a very low bearing capacity and high compressibility. Generally, a building construction on peat is done by using a wooden pile foundation. However, the length of the wooden piles is sometimes limited and causes the friction strength between the soil and wooden piles to became suboptimal. In order to enhance the bearing capacity of the foundation, the cross-sectional area of the foundation needs to be enlarged. One of the solutions for this problem is through helical piles. There are two methods to determine the helical pile`s bearing capacity, i.e. individual bearing and cylindrical shear methods. In this paper, bearing capacity prediction was discussed. A foundation load test was thoroughly done by a constant rate of penetration. This test consisted of compression and tension tests. The result was analyzed by individual bearing and cylindrical shear methods and next compared to each other. The result of the analysis has shown that the individual bearing method was more suitable in predicting helical piles’ bearing capacity since it produced the lowest error rate, with a magnitude of 21,31%.


2015 ◽  
Vol 77 (11) ◽  
Author(s):  
Helmy Darjanto ◽  
Masyhur Irsyam ◽  
Sri Prabandiyani Retno

The Spider Net System Footing (SNSF) is a raft foundation system that commonly used in Indonesia. It contains a plate, downward ribs system for reinforcement, and the compacted filled soil. The ribs are in longitudinal and transversal, called as settlement rib and in diagonal direction, named as construction rib. This paper explores the load transfer mechanism along the plate, the ribs, filled soil and the base soil under the footing system. The mechanism is investigated by conducting full scale static load test on SNSF. Strain gauges were installed to monitor the strain increment of each footing elements during loading. 3D numerical analysis was also conducted to verify the experimental results. To analyze the results, Load-Ultimate Ratio Factor (L-URF) was proposed. L-URF was a ratio between ultimate soil bearing capacity of the SNSF and the applied loading at specific element. Higher the L-URF value means higher loading applied at its associate element. Both experimental and numerical results show that at the first stage the loading was fully carried out by the tip of the ribs and transferred to the soil stratum under the footing system. Increasing the loading, the ribs, plate, and filled soil altogether sustain the loading and then transferred to the soil stratum below the footing system. The results also affirm that SNSF generate higher bearing capacity compare with simple shallow footing.  


2013 ◽  
Vol 838-841 ◽  
pp. 854-857
Author(s):  
Rui Chao Cheng ◽  
Xin Yu

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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