دانلود گزارش کارورزی و کار آموزی

چکیده : 

Elastic–plastic, closed-form solutions were developed recently by the author, to capture the nonlinear

response of laterally loaded rigid piles. Presented in compact form, the solutions are convenient to use,

and sufficiently accurate despite using only two input parameters of the net limiting force per unit length

pu along the pile, and a subgrade modulus k. Nevertheless, piles may be subjected to limited caprestraints

or loading below ground surface, which alter the response remarkably.

This paper provides explicit expressions for estimating loading capacity of anchored piles and develops

new solutions for lateral piles with cap-rotation by stipulating a constant pu or a linear increasing pu (Gibson

pu) with depth. Lateral loading capacity Ho (at the tip-yield state and yield at rotation point state) and

maximum bending moment Mm (at the tip-yield state) are presented against loading locations, and in

form of the lateral capacity Ho Mo (applied moment) locus. The capacity is consistent with available

solutions for anchored piles, and caissons with either pu profile, allowing a united approach from lateral

piles to anchored piles. The new solutions are also presented in charts to highlight the impact of rotational

stiffness of pile-cap on nonlinear response, offering a united approach for free-head piles through

fixed-head piles.

Several advantages of the solutions are identified against the prevalent p–y curve based approach. To

estimate the key parameter pu, values of the resistance factor Np (=ratio of pile–soil limiting resistance

over the undrained shear strength su) are deduced using the current expressions against available normalised

pile capacity involving the impact of gapping (between pile and soil), pile movement mode, pile

slenderness ratio, inclined loading angle (anchored piles) and batter angles (lateral piles). The Np is characterised

by: (i) An increase from 5.6–8.6 to 10.14–11.6, as gapping is eliminated around lateral piles and

caissons, and from 1.0–6.1 to 2.8–9.8, as translation is converted into rotation mode of footings. (ii) Similar

variations with slenderness ratio between anchors and caissons (without gapping), and among

anchors, caissons and pipelines (with gapping). And (iii) A reduction with loading angles (anchors) resembling

that with batter angles (piles).

چکیده : 

Small strain consolidation theories treat soil properties as being constant and uniform in the course of

consolidation, which is not true in the case of electro-osmosis-induced consolidation practices.

Electro-osmotic consolidation leads to large strain, which physically and electro-chemically affects to a

non-negligible extent the nonlinear changes of the soil properties. For the nonlinear changes, iterative

computations provide a mathematical approximation of the soil consolidation when the time steps

and spatial geometry are intensively meshed. In this context, this paper presents a finite-difference

model, EC1, for one-dimensional electro-osmotic consolidation, and this model is developed based on

a fixed Eulerian co-ordinate system and uses a piecewise linear approximation. The model is able to

account for the large-strain-induced nonlinear changes of the physical and electro-chemical properties

in a compressible mass subjected to electro-osmotic consolidation and to predict the consolidation characteristics

of the compressible mass. EC1 is verified against exact analytical solutions and test results

obtained from an experimental program. Example problems are illustrated with respect to the numerical

solutions of large-strain electro-osmotic consolidation

چکیده : 

This paper presents the theoretical background of an elastic electro-osmosis consolidation model for saturated

soils experiencing large strains, which considers volumetric strains induced by changes in both

the hydraulic and electric driven pore water flows. Three fully coupled governing equations, considering

the soil mechanical behaviour, pore water transport and electrical field, and their numerical implementation

within an updated Lagrangian finite element formulation, are presented. The proposed model is

first verified against a classical one-dimensional analytical solution for electro-osmosis consolidation

to demonstrate its accuracy and efficiency. Then, various numerical examples are investigated to study

the deformation characteristics and time dependent evolution of excess pore pressure. Finally, the importance

of considering large strains in a consistent and proper way is demonstrated, and differences compared

to models based on small strain theory are highlighted.

چکیده : 

A channelized debris flow is usually represented by a mixture of solid particles of various sizes and water

flowing along a laterally confined inclined channel-shaped region to an unconfined area where it slows

down and spreads out into a flat-shaped mass.

The assessment of the mechanical behavior of protection structures upon impact with a flow, as well as

the energy associated to it, are necessary for the proper design of such structures which, in densely populated

areas, can prevent victims and limit the destructive effects of such a phenomenon.

In the present paper, a simplified analysis of the mechanics of the impact of a debris flow is considered

in order to estimate the forces that develop on the main structural elements of a deformable retention

barrier.

For this purpose, a simplified structural model of cable-like retention barriers has been developed – on

basis of the equation of equilibrium of wires under large displacement conditions, – and the restraining

forces, cable stresses and dissipated energies have been estimated.

The results obtained from parametric analyses and full-scale tests have then been analysed and compared

with the proposed model.