p.2
Settlement Estimation Methods
Why must foundation settlements be estimated with great care?
For buildings, towers, power plants, and similar high-cost structures.
p.2
Settlement Estimation Methods
What are the components of pile settlement prediction?
A sum of pile heel settlement and elastic deformation of the pile.
p.2
Settlement Estimation Methods
What can excessive settlement and differential movement cause?
Distortion and cracking in structures, especially for rotary machines.
p.2
Design Requirements for Power Plant Foundations
Why was a piled foundation chosen for the gas turbine structure?
Due to the soil's capacity to undergo great stresses and special equipment requirements.
p.7
Finite Element Method in Foundation Design
Which software was used to obtain reliable results of pile settlements?
Plaxis 3D Foundation package.
p.4
Settlement Estimation Methods
How is total settlement assessed for bored piles foundation?
As the sum of axial and point settlement.
p.5
Finite Element Method in Foundation Design
What model was used in Plaxis 3D Foundation for deformation analysis?
Elastic-plastic Mohr-Coulomb model.
p.2
Settlement Estimation Methods
What is the maximum allowable settlement according to guidelines?
Less than 2% of the diameter of the pile (D).
p.6
Static Load Testing of Piles
How was the load increased during the static load pile test?
Gradually, by 250 kN every hour.
p.1
Settlement Estimation Methods
What is the main focus of the paper?
Estimation of settlements of bored piles foundation at the Elektrenai power plant in Lithuania.
p.6
Settlement Estimation Methods
What is the purpose of estimating a constant average stiffness for each soil layer?
To enable relatively fast computations and obtain a first estimation of deformations.
p.1
Design Requirements for Power Plant Foundations
What were the dimensions of the piles used in the foundation?
880 mm in diameter and 29 m long.
p.2
Geotechnical Investigation Techniques
What types of tests were used to estimate soil properties?
Cone penetration tests, dynamic penetration tests, boreholes, excavations, and laboratory investigations.
p.6
Static Load Testing of Piles
What equipment was used to measure pile top displacements?
Dial gauges with an accuracy of 0.1 mm.
p.1
Comparison of Settlement Calculation Methods
What are some of the methods used for settlement calculation?
Bowles method, Schmertmann methods, EN 1997-2 method, NEN 6743 method, and finite element method in Plaxis 3D Foundation.
p.7
Static Load Testing of Piles
What does the green curve in the time-settlement curve represent?
Experimental results of the static load pile test.
p.5
Geotechnical Investigation Techniques
What software was used for computing settlements of bored piles foundation?
Geo5 software (Pile CPT) and Plaxis 3D Foundation.
p.2
Settlement Estimation Methods
What complicates foundation design significantly?
Soil parameters must be obtained on-site prior to project calculation.
p.2
Settlement Estimation Methods
What is the total estimated settlement value for the pile foundation at Elektrenai power plant?
15.6 mm, including 2.1 mm from elastic deformation.
p.5
Settlement Estimation Methods
What does the limit loading curve describe?
The variation of vertical load as a function of the pile settlement.
p.3
Soil Properties Analysis
What is the significance of the N values obtained from the SPT?
They provide useful information regarding the consistency of cohesive soils and the relative density of cohesionless soils.
p.7
Settlement Estimation Methods
Which method provided the largest value of bored pile settlement?
The analytical Bowles method.
p.7
Reliability and Safety Factors in Foundation Engineering
What is the significance of choosing appropriate safety factors?
It is important for the specific foundation type considering remarks from EN 1997-2 and Tomlinson criteria.
p.7
Settlement Estimation Methods
What does Bowles’ settlement criterion serve as in the analysis?
A conservative limit, indicating that real settlement should be lower than the estimated value.
p.7
Settlement Estimation Methods
What standards and approaches were employed for pile settlement analysis?
EN 1997-2, NEN 6743, Schmertmann and Bowles, and finite element method.
p.7
Design Requirements for Power Plant Foundations
What is the most appropriate method for this project according to the conclusions?
The EN 1997-2 ultimate limit stage method.
p.5
Settlement Estimation Methods
Which standards were followed for pile settlement analysis?
EN 1997-2, NEN 6743, and Schmertmann.
p.3
Design Requirements for Power Plant Foundations
What type of piles were adopted for the foundation in the study?
Bored cast-in-place piles with a diameter of 880 mm.
p.3
Geotechnical Investigation Techniques
What methods were used for soil investigation at the Elektrenai power plant site?
Boreholes, cone penetration tests (CPT), dynamic penetration tests (DPSH), and trial pits.
p.3
Design Requirements for Power Plant Foundations
What is the main purpose of a foundation in engineering?
To receive loads from equipment and transmit these loads to the piles.
p.3
Design Requirements for Power Plant Foundations
What are the three main steps in designing a deep pile foundation?
1. Determine DWL and SWL for a single pile. 2. Obtain bearing capacities and related settlements for several pile lengths. 3. Check the actual behavior of several grids of piles under the foundation slab.
p.5
Finite Element Method in Foundation Design
What parameters are involved in the Mohr-Coulomb model?
E, ν for soil elasticity; ϕ, c for soil plasticity; ψ as an angle of dilatancy.
p.3
Soil Properties Analysis
What geological layers were identified in the investigation area?
1. Medium to firm clay sediment. 2. Medium to coarse silty sand, dense. 3. Medium to coarse silty sand, medium dense. 4. Medium to coarse silty sand, very dense.
p.1
Geotechnical Investigation Techniques
What types of tests were conducted to gather soil data?
Cone and dynamic penetration tests, boreholes, and laboratory tests.
p.2
Design Requirements for Power Plant Foundations
What is the significance of the combined unit of gas turbine, generator, and steam turbine?
It induces high loads, requiring adequate resistance from the foundation.
p.1
Impact of Soil Capacity on Foundation Design
Why was a piling solution adopted for the power plant?
Due to insufficient soil capacity to support great stresses and high requirements for slab settlements and bearing capacity.
