scholarly journals Load-Bearing Characteristics of Large-Diameter Rock-Socketed Piles Based on Ultimate Load Tests

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Xueying Liu ◽  
Xiaoyu Bai ◽  
Mingyi Zhang ◽  
Yonghong Wang ◽  
Songkui Sang ◽  
...  
Keyword(s):  
Load Transfer ◽  
Large Diameter ◽  
Peak Load ◽  
Internal Force ◽  
Pile Diameter ◽  
Maximum Loading ◽  
Side Resistance ◽  
Load Tests ◽  
Resistance Performance ◽  
Ultimate Resistance

As part of a large converter project in Shandong Province, vertical static load tests and internal force tests were conducted on three large-diameter rock-socketed piles, their load transfer mechanism was clarified, and the ultimate side resistance and ultimate resistance performance characteristics of the rock-socketed sections were analyzed. The test results showed that the three test piles were damaged under maximum loading, the Q-s curve exhibited a steep drop, the pile compression was around 1.2 times the pile diameter, and the bearing capacity of a single pile did not meet the design requirements. The side and end resistances of the three test piles all reached their ultimate values, but the ultimate side resistance was lower than the lower limit of the recommended value in the current technical code for building pile foundations. The end resistance under maximum loading accounted for 38.4–53.8% of the peak load, which was relatively high. By comparing it with other studies, there was no significant correlation between the coefficient of rock ultimate side resistance of the rock-socketed segment and the pile diameter of the rock-socketed segment. However, the coefficient of ultimate resistance increased gradually with the pile diameter. However, the latter correlation was not significant when the pile diameter was less than 1000 mm.

Numerical investigation of the monotonic drained lateral behaviour of large diameter rigid piles in medium dense uniform sand

Géotechnique ◽  
2021 ◽  
pp. 1-39
Author(s):  
Huan Wang ◽  
M. Fraser Bransby ◽  
Barry M. Lehane ◽  
Lizhong Wang ◽  
Yi Hong
Keyword(s):  
Numerical Investigation ◽  
Load Transfer ◽  
Large Diameter ◽  
Offshore Wind ◽  
Soil Pressure ◽  
Lateral Capacity ◽  
Pile Diameter ◽  
Centrifuge Tests ◽  
Lateral Response ◽  
Loading Eccentricity

This paper presents a numerical investigation of the monotonic lateral response of large diameter monopiles in drained sand with configurations typical of those employed to support offshore wind turbines. Results from new centrifuge tests using instrumented monopiles in uniform dry sand deposits are first presented and used to illustrate the suitability of an advanced hypoplastic constitutive model to represent the sand in finite element analyses of the experiments. These analyses are then extended to examine the influence of pile diameter and loading eccentricity on the lateral response of rigid monopiles. The results show no dependency of suitably normalized lateral load transfer curves on the pile diameter and loading eccentricity. It is also shown that, in a given uniform sand, the profile with depth of net soil pressure at ultimate lateral capacity is independent of the pile diameter because of the insensitivity of the depth to the rotation centre for a rigid pile. A normalization method is subsequently proposed which unifies the load-deflection responses of different diameter rigid piles at a given load eccentricity.

Instrumented load tests in mudstone: pile capacity and settlement prediction

2002 ◽  
Vol 39 (6) ◽  
pp. 1254-1272 ◽  
Author(s):  
J R Omer ◽  
R Delpak ◽  
R B Robinson
Keyword(s):  
Load Transfer ◽  
Load Capacity ◽  
Large Diameter ◽  
Soft Rock ◽  
Site Investigation ◽  
Alternative Methods ◽  
Vertical Loading ◽  
South Wales ◽  
Pile Design ◽  
Load Tests

The present work stems from the design of a viaduct in South Wales, U.K., where full-scale pile testing was carried out to assess whether the proposed design methods would meet the required load capacity and settlement criteria for the working piles. Five fully instrumented large diameter bored cast in situ piles, up to 30 m deep, were installed in weathered mudstone and tested under vertical loading. A sixth pile, which had no shaft instrumentation, was formed with a voided toe. In conjunction with vast soil data from 218 site investigation boreholes, the extensive data produced from the load tests were analyzed to quantify the key parameters considered to influence load transfer and settlement behaviour. Each pile was first calibrated using four methods to establish the as-built stiffness, taking into account the nonlinearity of concrete and the effect of partial steel encasement. It is demonstrated that the current national norms for bored pile design in cohesive soil – soft rock are overconservative for South Wales ground conditions. To ameliorate this, alternative methods are proposed, which lead to improved reliability and accuracy in shaft and base capacity assessment. In addition, a numerical model is developed that can be used to predict the complete load-settlement variation up to the ultimate state. The model is sufficiently expounded to allow its immediate application in pile design by geotechnical engineers.Key words: piled foundations, load tests, bearing capacity and settlement, Mercia mudstone.

Design of bored piles in residual soils based on field-performance data

1991 ◽  
Vol 28 (2) ◽  
pp. 200-209 ◽  
Author(s):  
M. F. Chang ◽  
B. B. Broms
Keyword(s):  
Load Transfer ◽  
Large Diameter ◽  
Design Procedure ◽  
Field Performance ◽  
Residual Soil ◽  
Residual Soils ◽  
Weak Rocks ◽  
Load Tests ◽  
Bored Piles ◽  
Load Displacement

The current practice for the design of large-diameter bored piles in residual soils in Singapore is based on the calculated static capacity of the piles. Insufficient consideration of the load-transfer mechanism and overreliance on pile load tests have led to conservative designs. A better alternative is to adopt a load–displacement analysis method that provides information on the load distribution along the pile and the complete load–displacement relationship. Results of full-scale load tests on instrumented piles indicate that bored piles in residual soils in Singapore behave in the same way as in stiff clay and weak rocks elsewhere in that the load transfer at the working load is dominated by shaft friction. Simple correlations exist between the standard penetration resistance and the load-transfer parameters. An example illustrates that the proposed design procedure that uses these simple correlations and the load-transfer method is an improvement over present design methods. Key words: bored piles, cast-in-place piles, design, drilled piers, field test, load transfer, residual soil, shaft resistance.

Situ Tests of Bearing Character on Large Diameter Deep Socketed Pile in Qingdao Gulf Bridge

2012 ◽  
Vol 178-181 ◽  
pp. 2501-2504
Author(s):  
Chun Lin He ◽  
Cheng Zhong Gong
Keyword(s):  
Large Diameter ◽  
Bridge Engineering ◽  
Test Results ◽  
Long Span ◽  
Long Span Bridge ◽  
Side Resistance ◽  
Load Tests ◽  
Bearing Characteristic ◽  
Side Friction ◽  
The Relationship

With the development of long-span bridge engineering and increase of load on construction, the piles which socketed in rock more than 5 diameters have been used in some bridge engineering. Based on the technique of Anchored piles method, the static load tests of large diameter and deep socketed piles had been carried out in Qingdao Gulf Bridge. The bearing characteristics of large diameter pile were analyzed, including the load displacement curves of test pile; the axial force; the relationship between side friction and displacement and the sharing ratio of side resistance and end resistance. Finally, the test results were compared with specifications, The results showed that the bearing characteristic of deep socketed piles was as same as the friction piles in this area; from the results of test the side friction of pile could be estimated lower in strongly weathering breccia area while the friction in strong- weakly weathered breccia was relatively close to the value of exploration reports. At the bottom of the pile, because the relatively displacement of pile-rock was small, the pile side resistance is relatively small. It could be seen that the estimate of bearing capacity was less than the test result, and the pile foundation was safety enough.

Experimental Investigation Into Pile Diameter Effects of Laterally Loaded Mono-Piles

2011 ◽  
Author(s):  
Etienne A. Alderlieste ◽  
Jelke Dijkstra ◽  
A. Frits van Tol
Keyword(s):  
Cyclic Load ◽  
Large Diameter ◽  
Load Control ◽  
Geotechnical Centrifuge ◽  
Lateral Capacity ◽  
Current Test ◽  
Pile Diameter ◽  
Validity Range ◽  
Load Tests ◽  
Laterally Loaded

This paper presents the results of model tests on laterally loaded mono-pile foundations in sand. The tests have been performed in a geotechnical centrifuge. The objective of the research is to quantify large diameter effects of these mono-piles on the lateral capacity and the stiffness response for cyclic lateral loading. These large diameters are out of the validity range of the commonly used design methods. For this reason prototype pile diameters up to 4.4 m with a length over diameter ratio of 5 have been investigated. The results show an increase in pile diameter from Ds = 2.2 m to Dl = 4.4 m leads to a significant increase in static lateral capacity and stiffness from cyclic load tests. All tests have been performed with constant L/D = 5, Id = 60% and a load eccentricity up to e = 4.8 m. However, the current test series needs to be extended to higher initial densities and the load control should be more strictly regulated before a clear diameter dependence, for pile diameters > 2.2 m, is proven.

Vertical Loading Test on the Bearing Capacity of Large-Diameter Filling-Piles in the Mudstone and Sandstone Foundation

2013 ◽  
Vol 639-640 ◽  
pp. 587-592 ◽  
Author(s):  
Hui Yang ◽  
Xue Liang Jiang ◽  
Jun Fu
Keyword(s):  
Bearing Capacity ◽  
Load Transfer ◽  
Large Diameter ◽  
Load Test ◽  
Sediment Thickness ◽  
Loading Test ◽  
Friction Resistance ◽  
Vertical Loading ◽  
Pile Diameter ◽  
Side Friction

Based on the vertical loading test results of large-diameter filling pile near an electric factory in the sandstone and mudstone foundation, the load transfer mechanism and vertical loading bearing behavior of the pile were discussed. The analysis shows that the pile mainly behaves as friction piles and the vertical bearing capacity is mainly supplied by side friction resistance. The pile side friction is related to the section displacement of pile, the pile load and the soil characteristic. The pile end resistence is related to pile end settlement, pile diameter, rock-socketed length,rock elasticity modulus of pile end, sediment thickness and pile construction technical. The pile end resistence linearly increases with the settlement of pile end. In tis paper, the dead-load test is recommended in determination the pile bearing capacity and the sediment thickness should be strictly controlled in order to meet the standard. In the intermediary weathered sand-mudstone, the pile end should inset two times of pile diameter for pile whose diameter is 800mm. The pile end should inset 2 meters for pile whose diameter is 1500mm.

scholarly journals Field Tests of Super-Long and Large-Diameter Drilled Shaft Pile Foundations

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Peisen Wang ◽  
Hongyan Ding ◽  
Jialin Zhou ◽  
Wenjun Hu ◽  
Xuechen Gu ◽  
...  
Keyword(s):  
Load Transfer ◽  
Large Diameter ◽  
Soil Layer ◽  
Field Tests ◽  
Load Test ◽  
Pile Foundations ◽  
Static Load Test ◽  
Mutual Compensation ◽  
Shaft Resistance ◽  
Pile Diameter

This study investigated the compressive behaviour of super-long pile foundations with large diameters. Three 52 m, 73 m, and 83 m long piles with a diameter of 1500 mm, 1500 mm, and 1800 mm were cast and tested, respectively. Given that large loading was required, an improved compressive static load test was introduced, and the load transfer mechanism, shaft resistance development, and distribution were analysed. This study found that the transferred load decreased along the pile during each applied load, but the gradients were different. For most layers, when increasing the load, the shaft resistance developed in the upper layers first, while the shaft resistance from the lower part did not always fully develop. Moreover, the “mutual compensation” phenomenon was discovered, which was when the shaft softening occurred from one soil layer, the shaft hardening of the other soil would occur simultaneously. Under consideration of the soil layer differences around these piles, it was recommended that shaft and base grouting should be applied on 52 m and 73 m piles, while only shaft grouting should be applied on the 83 m pile. For this longest pile design, whose toe resistance was discovered to be very small, increasing the pile length was not appropriate; thus, it was preferable to increase the pile diameter to increase the ultimate bearing capacity.

Field static load tests on drilled shaft founded on or socketed into rock

2000 ◽  
Vol 37 (6) ◽  
pp. 1283-1294 ◽  
Author(s):  
Caizhao Zhan ◽  
Jian-Hua Yin
Keyword(s):  
Bearing Capacity ◽  
Static Load ◽  
Large Diameter ◽  
Load Test ◽  
Drilled Shaft ◽  
Test Results ◽  
Static Load Test ◽  
End Bearing Capacity ◽  
Side Resistance ◽  
Load Tests

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.

scholarly journals Optimization Analysis of Settlement Parameters for Postgrouting Piles in Loess Area of Shaanxi, China

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Zhijun Zhou ◽  
Shanshan Zhu ◽  
Xiang Kong ◽  
Jiangtao Lei ◽  
Tong Liu
Keyword(s):  
Compression Modulus ◽  
Summation Method ◽  
Cone Penetration ◽  
Optimization Analysis ◽  
Loess Area ◽  
Elastic Compression ◽  
Settlement Calculation ◽  
Side Resistance ◽  
Load Tests ◽  
The Relationship

The settlement calculation of postgrouting piles is complex and depends on the calculation method and parameters. Static load tests were conducted to compare the settlement characteristics of nongrouting and postgrouting piles, and three vital parameters in the layer-wise summation method were revised to predict the settlement of postgrouting piles. The elastic compression coefficient was deduced based on the Mindlin–Geddes method by considering the influence of the change in the pile side resistance distribution and end resistance ratio on the elastic compression after grouting. The relationship between the compression modulus and soil gravity stress and cone penetration resistance were established, respectively, using experimental data. The optimum value of the settlement empirical coefficient was determined using regional data. Finally, we used the postgrouting pile of the Wuqi–Dingbian expressway as a practical example. The results obtained from the layer-wise summation method after parametric optimization were close to the measured values. The results of this study provide reference data and guidance for the settlement calculation of postgrouting piles in this area.

Experimental Study of the Rotary Filling Piles with Large-Diameter under the Axial Load

2012 ◽  
Vol 594-597 ◽  
pp. 527-531
Author(s):  
Wan Qing Zhou ◽  
Shun Pei Ouyang
Keyword(s):  
Experimental Study ◽  
Axial Load ◽  
Load Transfer ◽  
Soft Soil ◽  
Large Diameter ◽  
Shaft Resistance ◽  
Tip Resistance ◽  
Soil Foundation ◽  
Soft Soil Foundation ◽  
Deep Soft Soil

Based on the experimental study of rotary filling piles with large diameter subjected to axial load in deep soft soil, the bearing capacity behavior and load transfer mechanism were discussed. Results show that in deep soft soil foundation, the super–long piles behave as end-bearing frictional piles. The exertion of the shaft resistance is not synchronized. The upper layer of soil is exerted prior to the lower part of soil. Meanwhile, the exertion of shaft resistance is prior to the tip resistance. For the different soil and the different depth of the same layer of soil, shaft resistance is different.

Sign in / Sign up

Export Citation Format

Share Document