Showing papers on "Lateral earth pressure published in 1983"

Basic Soil Mechanics

Abstract: 1. Origins and Composition of Soil. 2. Classification of Soils for Engineering Purposes. 3. Basic Physical Properties of Soils. 4. Groundwater, Pore Pressure and Effective Stress. 5. Soil Permeability and Seepage. 6. Stresses and Strains in Soils. 7. Measurement of Shear Strength. 8. Earth Pressure and Retaining Walls. 9. Stability of Slopes. 10. Settlement and Consolidation. 11. Bearing Capacity of Foundations. 12. Site Investigations and In Situ Testing. Appendix A Eurocode 7: Geotechnical Design. Appendix B Geotechnical Design: Factors of Safety and Partial Factors. Appendix C Guide to Soil Mechanics Spreadsheets and Reference (on the CD-ROM).

Lateral earth pressures in expansive clay soils

Abstract: Lateral earth pressures produced by saturated clays with negative pore-water pressures and unsaturated expansive clays with positive matric suctions are considered from a theoretical standpoint. Si...

Lateral Earth Pressure

Abstract: This chapter deals with the magnitude and distribution of lateral pressure between a soil mass and an adjoining retaining structure. Conditions of plane strain are assumed, i.e. strains in the longitudinal direction of the structure are assumed to be zero. The rigorous treatment of this type of problem, with both stresses and displacements being considered, would involve a knowledge of appropriate equations defining the stress-strain relationship for the soil and the solution of the equations of equilibrium and compatibility for the given boundary conditions. The rigorous analysis of earth pressure problems is rarely possible. However, it is the failure condition of the retained soil mass which is of primary interest and in this context, provided a consideration of displacements is not required, it is possible to use the concept of plastic collapse. Earth pressure problems can thus be considered as problems in plasticity.

Probabilistic Pore Pressure Analysis for Seismic Loading

Abstract: Two probabilistic models are proposed to study the development of pore pressure in saturated sands under random loading. The first of these is based on laboratory data, while the second uses an analytically based effective stress technique. Both incorporate uncertainties in soil parameters, laboratory data, and earthquake loading parameters, and compute the cumulative distribution function of pore pressure at the end of any cycle of loading. The two models are cast into a methodology which evaluates the probability of developing a certain level of pore pressure over a given time frame under a specified probability of seismic loading. They allow probabilities to be defined as to the generation of any pore pressure ratio from 0 to 1. They are suited to assess the relative effects of soil resistance, seismic environment, and geotechnical uncertainty. Limitations in application of the methods lie primarily in definition of soil and seismological parameters; however, future basic research should help to resolve this problem.

Anchored Sheet Pile Bulkheads: Design Practice

Abstract: The state of the art of sheet pile bulkheads design and investigation is reviewed. Using some examples of relatively recent large scale model tests and full scale investigations it is shown that the Coulomb Theory of earth lateral pressure against retaining structures with some empirical modifications could be used in design of anchored sheet pile bulkheads. However, in some cases of full scale investigations of anchored bulkheads it was found that the value of lateral soil pressure exceeded the value of minimum active pressure, as determined by Coulomb Theory, and it was close to “at rest” pressure. This phenomenon is explained by the soil “heredity” effect.

Performance and design of slurry walls in soft clay

Abstract: Extensive field tests on instrumentation, construction control, etc. were carried out on the performance and design of slurry trench walls in soft clay. These tests were designed to establish criteria and methods for evaluating the stability of slurry-filled trenches in soft day, to acquire data on the practical aspects of such construction, and to determine the performance of slurry-trench walls as earth-retaining structures. This article documents some of the extensive data that was gathered. The study found that there were on particular problems associated with construction of slurry-trench walls in soft clay. It is possible to construct such walls in soft clay with only clean water as supporting fluid. The special use of cross-lot walls to prevent bottom heave failure functioned well for two tunnel projects that were studied. For economical design, it is necessary to apply analytical methods that account for the interaction between soil-wall and support system and the actual sequence of excavation and installation of supports. It was found that earth pressures increased with time after completion of construction and approached the at-rest condition.

Construction work of foundation pile

Abstract: PURPOSE:To construct a pile having a multi-stage spherical footing by a method in which a rubber bag is set with a steel pipe under the ground, and concrete is placed into the bag. CONSTITUTION:A steel pipe 1 whose outside is covered with a rubber bag 2 and the tip is fitted with a shoe 3 is set under soft ground, and while concrete 8 is placed into the steel pipe 1 from a concrete placing pipe 7, the steel pipe 1 is pulled up. In this case, the rubber bag 2 is expanded sideways under the pressure of the concrete 8, and the expansion is stopped at the time when the soil pressure is balanced with the concrete pressure. By this, the places where soil pressure is small of the rubber bag 2 are projectionally expanded into wens form and thereby a pile with a multi-stage spherical footing can be constructed without wasting concrete.

Overall Stability of Anchored Retaining Walls

Abstract: Methods of checking the overall stability of anchored retaining walls are reviewed. Series of laboratory scale tests were carried out in which field construction of anchored rigid retaining walls was simulated. For each of four different anchor arrangements four methods which are used in practice to check overall stability, were used for the anchorage design. Considerable instrumen tation was incorporated in the test equipment so that wall and sand move ments, anchor forces and earth pressure acting on the wall could be monitored at all stages of the construction process. After completion of the excavation in front of the wall, the backfill was subjected to a uniform surcharge loading to increase stress levels above those used in design. All four design methods resulted in stable systems both at the end of construction and after backfill loading. However, wall movements when surcharge loading was applied to the backfill were considerable, and may not be acceptable in practice. Modifications to the design ...

Study of the lateral pressure of fresh concrete as related to the design of drilled shafts.

Abstract: A series of tests were conducted to determine the effect of the consistency of concrete, as measured by the slump test, on the lateral pressure of concrete. Testing conditions simulated the construction of drilled shafts as practiced by the Texas State Department of Highways and Public Transportation. The tests showed that increasing the slump of the concrete increased the maximum pressure and the length of shaft which was under hydrostatic conditions. Pulling the tremie increased the lateral pressure by variable amounts in an unpredictable manner. The increased pressure against the sides of an excavation is desirable because the axial capacity of a drilled shaft is increased.

Underground room such as notably a cellar

Abstract: The present invention relates to an underground room, such as notably a cellar, including a floor, a ceiling and lateral walls formed notably by stacked box-sections, prefabricated from concrete, the entire assembly being accommodated in an excavation sunk under a floor slab of a structure, this excavation being lined with a fluid-tight enclosure and provided with a bed of sand. The underground room has vertical posts or columns of reinforced concrete extending from the floor to the level of the ceiling thereof, and having a portion of a predetermined shape. The walls of the stacked box-sections have vertical edges of a shape corresponding to the predetermined shape of the portion of the columns, with the vertical edges bearing against the columns so that the box-sections act as supporting walls to withstand the earth pressure.

The design of reinforced soil walls by compaction theory

Abstract: Currently, two design philosophies are available for the design of reinforced soil walls. The first, known as the tie-back structure hypothesis, models lateral earth pressures using simple active pressure theories. This presupposes that the top of the wall rotates actively outwards about its toe. It is further assumed that failure in the soil occurs along a planar surface. The second and later approach, known as the coherent gravity structure hypothesis, assumes lateral earth pressures to vary from the "at rest" condition at the top of the wall to the active condition further down the wall. This is coupled with the assumption of a logarithmic spiral failure surface. To achieve compatibility between these two assumptions there is the further assumption that the base of the wall rotates actively outwards about its top. This assumption is compared with field observations which clearly indicate wall rotation about the toe. Since neither of these theories quantifies the effects of compaction, a theory is introduced to relate compaction-induced earth pressures to basic compaction plant characteristics. Results from this compaction theory are then compared with those from several case histories. Finally, a comparison is drawn between the three design methods, and comments are made on the resulting design implications. (Author/TRRL)

Construction work of underground structure

Abstract: PURPOSE:To raise the accuracy and efficiency of construction work by a method in which a structure oonsisting of pillars, wale and beams is formed in a wall- shaped trench excavated underground so that it can share the pressure of surround ground and water pressure and also the numbers of temporary materials are reduced. CONSTITUTION:In a wall-shaped trench 1 excavated underground and subjected to a mud-water treatment in advance, pillars 2 are fixed at given intervals by a temporary fitting tool 24, a proper number of beams 4 are laid, a strength wall 3 is inserted and joined through a T-shaped guide rail and coupler 12 and a T-shaped tool 13, the ground inside the structure is excavated to a given flooring face 8, a foundation slab (not illustrated) is set and joined with a foundation beam 4', and a floor slab (not illustrated) is laid and connected with the beam 4. Thus, the structure can be constructed with a high accuracy and also can withstand surround soil pressure and water pressure, and the numbers of temporary structures can be reduced.

Control or air pressure in hollow pipe for sand pile construction

Abstract: PURPOSE:To optimize the control of air pressure by using a control system in which air supply and discharge operations are automatically controlled in such a way that the air pressure inside a hollow pipe is regulated between the lower set pressure corresponding to soil pressure at the lower end of the hollow pipe and the upper set pressure. CONSTITUTION:An air supply pipe 5 with a switch valve 9 and a discharge pipe 6 with an air exhaust valve 7 are connected to a hollow pipe 1 through which sand is discharged into soft ground. Signal of a pressure sensor 8 provided to the pipe 1 is put, together with signals of a depth meter 11, etc., in a meter 13. In the drawing process of the pipe 1 (discharge process of sand), while regulating the air pressure inside the pipe 1, detected by the sensor 8, by the meter 13 in such a way that the air pressure is set within the lower limit set pressure corresponding to the soil pressure at the lower end of the pipe 1 and the upper limit set pressure slightly greater than the lower limit set pressure, detected by the depth meter, the pipe 1 is drawn and sand is discharged.

Effective stress analysis of the stability of embankments on soft soils: Discussion

Abstract: The authors are to be congratulated for their very clear and useful paper, which points out the efficiency of the effective stress analysis applied to embankment stability on soft soils, provided that the actually observed in-situ pore pressures are introduced into the analysis. We agree with the authors in their comments on the relative merits and shortcomings of the total and effective stress approaches. In cases in which significant consolidation takes place during the construction period, the effective stress analysis is the only efficient one. Regarding the improvements carried out in the last years to the total stress analysis, summarized by the authors in their introduction, a model has been presented by the writers in which the influence of the clay stress history on the undrained shear strength is taken into account (Ballester and Sagaseta 1979). The proposed yield condition is an anisotropic extension of Tresca's criterion. It is a total stress limit condition, but it is defined by the intrinsic effective strength parameters and the clay stress history. Thus, the model parameters are: -Hvorslev's parameters ( k, +,) -degree of friction mobilisation, DM (0 5 DM 5 1) -overburden effective pressure, p,' -overconsolidation pressure, p,' -lateral earth pressure coefficient, KO The variation with depth of the last three parameters produces strength gradient with depth. If KO # 1 .O, the behavior is anisotropic. The model has been implemented into a limit equilibrium analysis by the method of characteristics and applied in a general form to surface loads on soft clays (Arroyo and Sagaseta 1982). In order to check the validity of the model, it has been applied to a number of well-documented embankment failures, namely those of