Bearing capacity and settlement of weak fly ash ground improved using lime – fly ash or stone columns

2002 ◽  
Vol 39 (3) ◽  
pp. 585-596 ◽  
Author(s):  
Cheng Zhou ◽  
Jian-Hua Yin ◽  
Jing-Ping Ming
Keyword(s):  
Shear Strength ◽  
Fly Ash ◽  
Bearing Capacity ◽  
Negative Impact ◽  
Soil Layer ◽  
Stone Columns ◽  
Small Scale ◽  
Loading Test ◽  
Foundation Soil ◽  
Physical Tests

An experimental study was conducted to evaluate the suitability of lime for the improvement of weak fly ash ground. In the study, a series of unconfined and confined compression tests were carried out on cylindrical samples in the laboratory and on cubic samples in the field, of Lime-FA (lime – fly ash) mixtures with various mixing contents of lime and curing times. Some samples were compressed under a soaking condition with water. A series of full-scale physical tests in the field and small-scale physical tests in the laboratory were conducted on a foundation (or rigid plate) on weak fly ash ground improved using Lime-FA or stone columns, which form a composite foundation. Some physical tests were carried out under a soaking condition. From the test and physical model study, it was found that the Lime-FA mixture has a larger shear strength than that of fly ash when the mixing content of lime is larger than 10%. When the weak fly ash ground is improved with Lime-FA columns, the bearing capacity of the fly ash ground is increased, and the settlement is reduced largely. However, when the ground is soaked under water, the corresponding shear strength of the Lime-FA mixture is decreased, the bearing capacity of the Lime-FA composite ground is decreased, and the settlement is increased. A plate loading test with soaking test on a layer of 1.15 m thick fly ash was also done in the laboratory. The test results show that the top fly ash layer is not suitable as a foundation soil layer and should be replaced with other granular soils, rather than simply compacted to a higher density, due to the negative impact of soaking. Results from the test program are presented and discussed.Key words: fly ash, lime, unconfined compressive strength, shear strength, bearing capacity, settlement, soaking.

scholarly journals A Full-Scale Experimental Study of the Vertical Dynamic and Static Behavior of the Pier-Cap-Pile System

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jianlei Liu ◽  
Meng Ma ◽  
Flavio Stochino
Keyword(s):  
Experimental Study ◽  
Bearing Capacity ◽  
Dynamic Stiffness ◽  
Soil Layer ◽  
Low Frequency ◽  
Full Scale ◽  
Single Pile ◽  
Static Stiffness ◽  
Loading Test ◽  
Test Technique

The bearing capacity evaluation of bridge substructures is difficult as the static loading test (SLT) cannot be employed for the bridges in services. As a type of dynamic nondestructive test technique, the dynamic transient response method (TRM) could be employed to estimate the vertical bearing capacity when the relationship between static stiffness and dynamic stiffness is known. The TRM is usually employed to evaluate single piles. For the pier-cap-pile system, its applicability should be investigated. In the present study, a novel full-scale experimental study, including both TRM test and SLT, was performed on an abandoned bridge pier with grouped pile foundation. The test included three steps: firstly, testing the intact pier-cap-pile system; then, cutting off the pier and testing the cap-pile system; finally, cutting off the cap and testing the single pile. The TRM test was repeatedly performed in the above three steps, whereas the SLT was only performed on the cap-pile system. Based on the experimental results, the ratio of dynamic and static stiffness of the cap-pile system was obtained. The results show that (1) in the low-frequency range (between 10 and 30 Hz in this study), the dynamic stiffness of the whole system is approximately four times of that of a single pile; (2) the ratio of dynamic and static stiffness of the cap-pile system tested in the study is approximately 1.74, which was similar to other tested values of a single pile; (3) to evaluate the capacity of similar cap-pile system and with similar soil layer conditions by TRM, the value of Kd/Ks tested in the study can be used as a reference.

scholarly journals Reliability analysis of an end-bearing pile with account for friction forces on the pile surface

2020 ◽  
pp. 2-2
Author(s):  
Vladimir S. Utkin
Keyword(s):  
Bearing Capacity ◽  
Reliability Analysis ◽  
Limit State ◽  
Soil Layer ◽  
Material Behavior ◽  
Performance Criteria ◽  
Soil Behavior ◽  
Foundation Soil ◽  
Friction Forces ◽  
End Bearing Pile

Introduction. The behavior of end-bearing piles in the foundation soil and the methodology for their reliability analysis, treated as operational safety measures applicable to a separate bearing element of a pile foundation, need clarification and further development. The weakness of the established reliability analysis methodology, focused on the bearing capacity of the foundation soil, is its failure to take account of each case of the soil behavior above rock or low compressibility soils pursuant to Construction rules and regulations 24.13330.2011. Taking account of the bearing capacity of this soil layer in respect of the load accommodation by an end-bearing pile (taking account of the pile weight) may improve its reliability by the criterion of the bearing capacity in combination with the soil behavior below the bottom tip of a pile. Nizhne-Suyanskiy Waterworks Facility had the mission to solve water household, energy and socio-economic problems. Materials and methods. The author analyzed piles made of any applicable materials; their reliability analysis methods are based on the possibility theory due to the limited amount of statistical information on controllable parameters to be entered into the limit state design model to verify the bearing capacity of the foundation soil. Results. The author presents the design formula to identify the parameters ensuring reliable failure-free behavior of an end-bearing pile in the foundation soil and in respect of the soil bearing capacity. The pile reliability analysis performed in respect of its bearing capacity (and focused on the strength of the pile material) is provided in the references section. The author uses two performance criteria to analyze the reliability of an end-bearing pile, given that an end-bearing pile is analyzed as a consistent mechanical system in terms of the reliability theory. Conclusions. The author has developed a methodology used to analyze the reliability of end-bearing piles. It is focused on the bearing capacity of the foundation soil below the bottom tip of a pile and along its length with a view to the quantitative assessment of its safe performance at the stage of design of a facility that has a piled footing; the groundwork has been laid for further research into the behavior of end-bearing piles and for the development of design regulations applicable to various types of piles that may differ in material, behavior, sinking techniques, etc.

Experimental and Statistical Study on Single and Groups of Stone Columns

2020 ◽  
Vol 857 ◽  
pp. 399-408
Author(s):  
Maki J. Mohammed Al-Waily ◽  
Mohammed Y. Fattah ◽  
Maysa Salem Al-Qaisi
Keyword(s):  
Shear Strength ◽  
Stress Concentration ◽  
Bearing Capacity ◽  
Soft Clay ◽  
Undrained Shear Strength ◽  
Stone Columns ◽  
Stone Column ◽  
Dependent Variables ◽  
Undrained Shear ◽  
Improvement Ratio

In the present study, 24 laboratory models on soft clay treated with stone columns were carried out. The results for each case are analysed for the purpose of constructing a statistical model linking the variables studied. The experiments showed that the stress concentration and bearing capacity of soil treated with stone column increase with increasing the undrained shear strength (cu), number of columns and L/d ratio. The models represent a single stone column and a group of stone columns. The studied variables are three dependent variables, the stress concentration ratio (n), bearing capacity of soil treated with stone column (q) and the settlement improvement ratio (Sr) due to the existence of stone columns. The independent variables are six: the undrained shear strength of clay soil, with three values (6, 9 and 12 kPa), the number of stone columns (1, 2, 3 and 4 columns) and the length (L) to the diameter (D) of the stone column or (L/D) ratio in two values (6 and 8). Besides, the bearing capacity of the soil treated (q) with stone columns and the settlement improvement ratio were used in some statistical models as independents. After regression analysis, a set of equations that correlate the previous variables have been suggested. The incepted values for dependent variables are close to the laboratory results.

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.

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.

scholarly journals Settlement of Geosynthetic Encased Stone Columns Liquefaction Condition in Box Culvert

2021 ◽  
Vol 21 (1) ◽  
pp. 40-51
Author(s):  
Maftuh Ahnan ◽  
◽  
Putera Agung Maha Agung ◽  
Keyword(s):  
Bearing Capacity ◽  
Soil Layer ◽  
Soil Improvement ◽  
Stone Columns ◽  
Liquefaction Potential ◽  
The Stability ◽  
Unsafe Condition ◽  
Box Culvert ◽  
Settlement Analysis ◽  
Spt Data

When the box culvert system is placed on a sandy soil layer with a relatively low bearing capacity and is disposed to potential liquefaction, the soil layer must be repaired to avoid damages to the box culvert structure. The proposed method is Geosynthetic Encased Stone Columns (GESC) to increase the bearing capacity and anticipated the liquefaction potential. however, to meet the criteria for a stable and safe GESC soil improvement in liquefaction conditions, the value of the settlement must meet the requirements for the settlement permit limit. This research was conducted to determine the potential for liquefaction at the study location, to calculate the value of single and group settlements in liquefaction conditions and to analyze the stability of single and group settlements including safe or unsafe in liquefaction conditions. Analysis of liquefaction potential was analyzed based on SPT data using the Valera and Donovan method, and settlement analysis applied the Almeida and Alexiew method. The analysis shows that potential liquefaction due to an earthquake with a magnitude of 9.0 SR will be at a depth of 4 to 8 m. Single and group settlements (144 sets) with an installation distance of 1.2 m with a diameter of 0.4 m and at a depth of 10 m are 246.23 and 214.92 mm, respectively. The entire GESC system is considered to be in an unstable and unsafe condition against potential liquefaction and box culvert loading.

scholarly journals Shear Strength of Geopolymer Concrete Beams Using High Calcium Content Fly Ash in a Marine Environment

Buildings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 98 ◽  
Author(s):  
Muhammad Sigit Darmawan ◽  
Ridho Bayuaji ◽  
Hidajat Sugihardjo ◽  
Nur Ahmad Husin ◽  
Raden Buyung Anugraha Affandhie
Keyword(s):  
Shear Strength ◽  
Fly Ash ◽  
Marine Environment ◽  
Sea Water ◽  
Calcium Content ◽  
Shear Load ◽  
Geopolymer Concrete ◽  
Loading Test ◽  
High Calcium ◽  
Concrete Resistivity

This paper deals with the behavior of a geopolymer concrete beam (GCB) under shear load using high calcium content fly ash (FA). The effect of the marine environment on the shear strength of GCB was considered by curing the specimen in a sea splashing zone for 28 days. Destructive and non-destructive tests were carried out to determine the properties of geopolymer concrete in different curing environments. Geopolymer concretes cured at room temperature showed higher compressive strength, slightly lower porosity, and higher concrete resistivity than that of those cured in sea water. From the loading test of the GCB under shear load, there was no effect of a sea environment on the crack pattern and crack development of the beam. The shear strength of the GCB generally exceeded the predicted shear strength based on the American Concrete Institute (ACI) Code.

scholarly journals The behaviour of the clay soil reinforced by stone column encased with geogrid under cyclic load

2018 ◽  
Vol 1 ◽  
pp. 33-38
Author(s):  
Kwa S.F. ◽  
Kolosov E.S.
Keyword(s):  
Bearing Capacity ◽  
Cyclic Load ◽  
Clay Soil ◽  
Soft Clay ◽  
Soil Improvement ◽  
Stone Columns ◽  
Excess Pore Pressure ◽  
Stone Column ◽  
Foundation Soil ◽  
Saturated Clay

The behavior of the fully saturated clay soil reinforced by stone columns subjected to cyclic load is of considerable very important in the design of railway subgrades, these soft clay soil are characterized by high settlement and low bearing capacity because of the excess pore pressure due to heavy freight trains significantly reduces the bearing capacity which causes serious problems, the used of stone column for reinforced the saturated clay soil will reduced the settlement and increase the bearing capacity. The purpose of the current research is cases study of foundation soil improvement by reduced the settlement for a building structure using stone columns system with and without geogrid encasement under cyclic load with rate of loading 5 mm/sec.

scholarly journals Evaluation of Cohesive Soil Mixed With Fly Ash and Reinforced With Nylon Fibre

2017 ◽  
Vol 7 (2 (S)) ◽  
pp. 193
Author(s):  
Utkarsh Gawande ◽  
Shubham Kanhake ◽  
Arjun Lahane ◽  
Prasanna Naghbhide
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Fly Ash ◽  
Bearing Capacity ◽  
Unconfined Compressive Strength ◽  
Expansive Soil ◽  
Engineering Properties ◽  
Black Cotton Soil ◽  
Nylon Fiber ◽  
Properties Of Soil

Black cotton soil is a expansive soil. And mostly found in Vidarbha region of Maharashtra, this soil is highly unstable and it should be stabilize for carry out construction work. Materials like fly ash, rise husk, nylon fiber are used to make soil stable. Addition of such material will increase the physical, chemical and engineering properties of soil. Some of the properties which are improved are CBR value, shear strength, liquidity index, plasticity index, unconfined compressive strength (UCS) and bearing capacity, etc. The main objective of this study was to evaluate the effect of fly ash in stabilization of Black cotton soil. Mainly UCS and other properties of soil were calculated. The tests were conducted on Soil-Fly Ash mixtures, by increasing the Fly Ash percentage in Black cotton soil like 25%, 50%, 75%, and 100%, and then the soil was tested on Soil-Fly Ash - Fibre mixture by adding the fiber in increasing order like 0.5%, 1%, 1.5%. Results were obtained for mixed proportion of 75% soil and 25% fly ash which has unconfined compressive strength of 173 KN/m2. And by adding 1% of nylon fiber in same proportion of soil – fly ash the unconfined compressive strength increased to 243.12 KN/m2. Increase in UCS value can help in reducing the thickness of earthen roads and pavements and increase the bearing capacity and shear strength of soil. With analysis of results it was found that the fly ash along with nylon fiber has good potential to be used as an additive for improving engineering properties of expansive soil.

The Test Analysis of the Bearing Capacity of Foundation

2014 ◽  
Vol 962-965 ◽  
pp. 357-360
Author(s):  
Ya Jun Yin ◽  
Xue Wen Xie ◽  
Yong Mei Qian
Keyword(s):  
Bearing Capacity ◽  
Standard Penetration Test ◽  
Test Methods ◽  
Test Point ◽  
Load Test ◽  
Test Method ◽  
Penetration Test ◽  
Loading Test ◽  
Test Analysis ◽  
Foundation Soil

The test method of shallow plate load was used in the bearing capacity of foundation of Yushu City , doing two groups of loading test in different depths and doing survey and comparative test between test point nearby and sites in the same horizon.It gets the law of foundation soil bearing capacity value got by different test methods and provides the basis for Jilin Province to establish the local standards through the comparison of load test and geotechnical test , static cone penetration test and standard penetration test.

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