Showing papers on "Lateral earth pressure published in 1980"

Seismic p = y responses of flexible piles

Abstract: The finite element method was designed to solve soil-pile-structure interaction under seismic excitation by introducing "solid beam elements" to reproduce beam flexure and soil-pile interaction. Dynamic lateral load-deflection relationships were characterized by ratio of soil reaction per unit pile length to product of pile displacement relative to free-field motion and dynamic stress-strain properties of soil. Three hetergeneous soil profiles with equivalent linear approximation of nonlinear stress-strain behavior were used with this new finite element method to study the characteristics of dynamic lateral load-deflection relationships. Results were compared with those by other investigators and showed that the proposed method provided improved means of evaluating load-deflection relationships of piles. Results of this study were used to compute discrete soil-pile springs and dashpots for use in a beam-on-Winkler foundation model. (ASCE)

Effect of Total Load on Subsurface Soil Compaction

Abstract: TWO different size tires carrying unequal total loads that resulted in approximately equal soil surface pressures were run over soil pressure transducers buried at 18-, 30-, and 50-cm depths. The larger tire consistent-ly produced higher soil pressures at these depths. Froehlich's equation approximately described the soil pressure distribution in both a sandy soil and a clay soil with uniform density profiles. However, when a com-pacted layer was inserted in the density profile, this equation was no longer suitable. The data indicated no simple relationship between soil pressures and bulk densities.

Zero extension line theory of dynamic passive pressure

Abstract: A theory for dynamic passive pressure for sand is developed. The theory is based on a simplified zero extension line field. Equations and charts for computing the dynamic coefficient of earth pressure for various values of wall roughness are presented. The theory is capable of predicting an engineering solution to dynamic passive pressures for the cases of translation, rotation about the top, rotation about the bottom into loose or dense sand. The results are in agreement but generally higher than those predicted by the rigorous methods of associated fields.

Wind Resistance of Burley Tobacco as Influenced by Depth of Plants in Soil

Abstract: THE effect of a burley tobacco plant's depth in the soil on its resistance to lateral loads similar to those ex-erted by wind, was investigated. Forty-eight mature plants were tested in saturated Maury silt-loam soil. Depth in soil significantly affected lateral force required to produce a permanent set of 15 deg from vertical. A linear relationship was described between depth in soil and the rotational moment per unit stalk width required to produce a permanent set of 15 deg from vertical. The roots of a burley plant were found to provide only a small percentage of the total resisting moment offered by a plant against a lateral force, while the majority of resisting moment is provided by soil pressure against the in-soil portion of the stalk.

Simplified passive earth pressure analysis

Abstract: Determination of passive earth pressure acting on a rigid retaining wall is one of the most extensively studied stability problems in geotechnical engineering. Most methods of calculating passive pressures consider the soil mass to be limiting equilibrium and differ only in assumption about the shape of failure surface and variable soil properties the method of slices is widely used by practicing engineers to determine the earth pressure on a retaining wall. In this note a simple approach using the method of slices has been proposed for estimating passive earth pressure coefficients.

Earth pressures against an experimental retaining wall back filled with silty clay

Abstract: Details a study of compaction and swelling pressures developed by a clay backfill against two experimental retaining walls. The plasticity of the clay was well outside the upper limits for cohesive fill to structures.

Earth pressure balanced shield method

Abstract: A water pressure tunnelling method described is intended for use in driving tunnels in loose, subaqueous, sandy soil. The method allows safe and accurate tunnel excavation at normal speed without adverse effect on buildings even under unstable ground conditions. With this method soil excavated by the rotation of the disc of a shield machine is taken into the cutter frame and stored. The soil is compressed and transported backwards by the rotation of the screw conveyor. Earth pressure is generated to contain the earth pressure at the cutting face. Excavated soil is turned into a slurry for easy transport and discharge outside the tunnel. The tail void created by the movement of the shield can be filled by synchronous back-filling. Projects are described in which the tunnelling method was used in Tokyo on tunnels ranging from 1976-5240 mm diameter in complex soil composed of silt and gravel layers. (TRRL)

Determination of Seismic Earth Pressure on a Retaining Wall

Abstract: 1. The diagram of the intensity of the seismic pressure of cohesionless soil on a rigid retaining wall has the form of a triangle with a vertex at the base of the wall. 2. The seismic pressure of cohesionless soil on a rigid wall depends more on the elastic characteristics of the soil medium and considerably less on its angle of internal friction. 3. The standard method of determining loads from seismic earth pressure noticeably understates their extent and requires reexamination.

An introduction to soil mechanics and foundations. third edition

Abstract: One of the principal aims of this textbook is to provide the student with a description of soil behaviour, and of the effects of the clay minerals and the soil water on such behaviour. In the third edition, a few minor alterations have been made to take account of recent research. In addition, chapters have been rewritten to place the study of soil strength and consolidation more firmly in the context of plasticity theory, and to allow a fuller discussion of the methods of analysis of lateral earth pressure, stability of slopes and the bearing capacity of foundations. Chapters are as follows: the analysis and classification of soils; the clay minerals; pore pressure, effective stress and suction; permeability and seepage; a model for soil consolidation; a model for shear strength of soil; general soil models; plasticity, limit analysis and limiting equilibrium; lateral earth pressure; stability of slopes; bearing capacity of foundations; settlement of foundations; piled foundations; geotechnical processes; site investigation and in situ tests. (TRRL)

Laterally loaded pile groups

Abstract: This thesis is concerned with the problem of determining the response of pile groups to lateral loads. A model study is utilised to provide information on the effects of pile interaction and pile installation. The principal aim of the study was to define the effects of interaction between laterally loaded piles that have been installed by driving. Previous studies have ignored the effects of the installation process. The experimental programme was mainly involved with studying interaction between two piles in dense dry sand. The influence of pile interaction on the lateral load carrying capacity of each pile within the group, has been investigated in detail for various conditions of pile shape and stiffness, head fixity, and sand density. Three approaches were used to assess pile interaction. The first employed a stereophotogrammetric technique to observe the movement of sand particles. The second involved the determination of the lateral load resistance of each pile and the variation in this with pile deflection and pile spacing. Lastly a pile instrumented with pressure transducers was used to obtain the soil pressure distribution against each pile and to observe the changes resulting from pile interaction. Based on the information obtained from the measurement of soil pressures, the general response of sand to pile transmitted lateral loads is discussed. The results are compared with the commonly assumed values of soil stiffness and ultimate pressures. The effect of pile driving on the surrounding soil is studied. The driving process is shown to substantially alter the subsequent lateral response of each pile within the group. Previous model studies and current analytical techniques for assessment of pile interaction are reviewed. An analytical method of allowing for pile interaction, based on the results of the experimental study, is presented. This new technique is considered to give more realistic estimates of pile interaction, especially in the way it affects individual piles within a group. Charts are presented, from which an assessment of the maximum likely effects of interaction can be easily obtained without the need for a rigourous analysis. (TRRL)

Translational behaviour of gravity retaining walls during earthquakes

Abstract: The translational behaviour of gravity retaining walls during earthquakes is examined using two models--a simple sliding block model proposed by Richards and Elms, and Zarrabi's double block model. The behaviour of small retaining walls when subjected to horizontal excitation on the University of Canterbury's shaking table is compared to that predicted by the above theoretical models. In general, Zarrabi's model was seen to provide better estimates of the translational behaviour of the small gravity retaining wall. However, the simple sliding block model gave conservative estimates of total displacements, and in most cases the differences were not great. Zarrabi's computer program is extended to model the translational behaviour of a retaining wall with vertical and horizontal loads and with passive pressure at the wall toe. (TRRL)

Method for withdrawal of existing pile

Abstract: PURPOSE:To enable work on a provisional stand limited in weight by a method wherein the soil layer around an existing pile is softened by bits and pressurized water injected from injection ports, and the pile is drawn up, in a process of drawing the existing pile driven into weak ground or the like. CONSTITUTION:A lower end portion 1a of a device main body 1 is set upright on a soil layer in such a manner as to surround a head portion of an existing pile such as of H-steel (not shown), the main body 1 is rotated by a driving unit 7, and excavation bits 3 excavate the soil layer around the pile. The excavation is conducted while compensating for an excavation power of the bits 3 by injection of jet water from injection nozzles 4, and continued until the removal of a soil pressure is completed for a whole length of the pile. In this case, the excavated soil becomes into muddy water, and discharged to the surface by muddy water draining holes 6 and a thread 2. After the excavation, the main body 1 is removed, and the existing pile from which the adhered soil has been washed away by the muddy water is drawn out of the soil layer by a crane.

Applications of Slurry Walls in Civil Engineering

Abstract: Slurry wall (also called diaphragm wall) construction developed in the last three decades is a relatively new technique in civil engineering. It has been applied to a variety of projects in difficult soil and ground-water conditions. A brief description of construction procedures and design principles is given. Stability of the trench during excavation is an important consideration especially when ground movements in adjacent areas are to be minimized. In general, trenches remain stable when the hydrostatic pressure of the slurry is at least 65% to 80% of the outside pressures. Other forces imparting stability are not fully understood although various theories exist to explain them. Soil arching due to limited trench dimension is an important factor. Examples are given for application of slurry walls for seepage cutoff, basement walls, foundation pits, deep shafts, vibration control, underpinning alternatives, bridge foundations, quays and dock walls, slope stabilization, sewage projects, load bearing elements, and for cut-and-cover tunnels.

Burying method for pipe

Abstract: PURPOSE:To decrease an earth pressure acting against the installed pipes due to a sinking of the ground etc by a metod wherein a sheet or plate having a small coefficient of friction with respect to the earth is buried substantially vertically against a sliding plane of the ground CONSTITUTION:Since it is hard to hold only the sheet 10 having a small coefficient of friction with respect to the earth, the guide steel rods 11 are vertically installed at longitudinal both sides of the pipe 1 along the sliding surface with being properly spaced apart The sheets 10 are fixed by the bind wires 13 and the sheets 10 are extended over all sliding surfaces up to the surface ground When the back filling earth 14 is filled up to such a place as the pipe 1 is substantially hid, the sheets 10 are fixed to the guide steel rods 11 by the bind wires 13 and then all the back- filling earthes 15 are filled

Soil pressure meter of liquid pressure detection type

Abstract: PURPOSE:To improve the reliability by supporting the circumference of a pressure receiving plate having a large thickness on a container side wall through a thin plate and by filling a liquid into the inside. CONSTITUTION:An annular thin plate 6, which has a rigidity as low as possible but can endure the maximum of the coil pressure to be measured, is placed on the upper side of a side wall 2 having a bottom plate 3 on which a cross-shaped frame 4 is mounted. A pressure receiving plate 8 having a high rigidity and a large thickness is integrally fixed by means of rivets to the upper side of the supporting side of annular shape which is disposed at the inner and lower side of the thin plate 6 in a manner to clamp the thin plate 6, and its inside filled up with a liquid. As a result, the area of the plate 8 is enlarged to eliminate the influences due to the action of the local soil pressure. By thickening the plate 8, this plate 8 is uniformly displaced in a rigid manner even for the inevitable local soil pressure so that the abnormal change in the liquid pressure of the pressure meter, which is generated in accordance with the soil pressure can be prevented.

Construction of a root-pile wall at monssen, pennsylvania

Abstract: A case history of the design, analysis, construction, and performance evaluation of a root-pile wall is presented in this paper. The root-pile was contracted for construction by the Pennsylvania Department of Transportation to correct a landslide near Monessen. The structure consisted of four hundred and fifty-eight 12.5-cm (5-in.) diameter cast-in-place concrete piles placed at different inclinations to both the vertical and the horizontal axes. The piles were connected at the top by a 76.2-cm (30-in.) thick by 1.82-m (6-ft) wide cap beam constructed in two 30.48-m (100-ft) sections. The cap beam was constructed first, and the root piles were then installed by extending drill holes thorugh the cap beam to bedrock at predetermined locations and inclinations, inserting a single No. 9 deformed reinforcing steel bar (grade 60) into each drill hole, and grouting the holes. Nine survey targets were marked at the top of the cap beam to measure both horizontal and vertical movements and seven slope inclinometers were installed at various points both upslope and downslope from the structure to measure horizontal movements of the structure and the surrounding soil. This paper describes the soil and groundwater conditions, soil test results, slope stability analyses, design of the root-pile wall, and the findings of the horizontal and vertical measurements of wall movement. The following summary, observations, and conclusions are made: (a) a root-pile structure provides a fast and economical alternative to many conventional structures; (b) before the installation of the root piles, the movements of the cap beam varied from less than 2.5 cm (1 in.) at the north end to more than 45.7 cm (18 in.) at the sound end--these movements were due to movements of unstable soil in the slide area; (c) after the installation of the root piles, there were significant movements (up to 5 cm (2 in.)) in the cap beam as well as in the soil below it, which indicated that some movement of the root-pile structure was needed before resistance to earth pressure could be mobilized; (d) no significant soil movement through the root piles could be detected--the small-diameter piles and the soil between them appeared to work as a single composite structure; and (e) conventional design procedures for retaining walls appear to provide adequate overall design for root-pile walls (the geometry of the root-pile structure described in this paper is patented and may not be the optimum design for all situations). (Author)

Design of reinforced earth for New Zealand conditions

Abstract: Reinforced Earth (R/E) is a patented system for the construction of earth retaining structures, which has been developed and is used extensively overseas. The system is now available in New Zealand, the licence holder being Reinforced Earth Limited. This paper briefly reviews the use, advantages, disadvantages, design methods, patented components and construction techniques associated with R/E retaining structures. Seismic design of R/E structures is discussed in general and a particular seismic design method is considered in detail. The paper also describes the design of a large R/E retaining wall, of 1800 m area and 13 m maximum height, in a seismically active area of New Zealand. A simplified empirical seismic earth pressure loading is proposed for approximate design.