Earth pressure balance (EPB) shields can be operated so that soil is forced away from its face; this heaving process may cause smaller surface settlements than would result from tunneling, without inducing any initial heave. Field observations made at the first EPB project in the U.S. and finite element analyses results of that project are compared to gain a better understanding of ground behavior around EPB shields. Field observations indicated that the ground response was both three‐dimensional and time‐dependent. To keep computational costs within reason, the EPB tunneling process was simulated in a finite element analysis using two, two‐dimensional models. Besides approximating EPB shield tunneling effects, the finite element simulations explicitly account for pore pressure mobilization and dissipation in time. Results of parametric studies indicate that intentionally induced heave decreases the net movement into the tail void gap behind the shield at the expense of increasing consolidation settlements at the surface.

A parametric study of the seismic response of a chosen site was conducted to demonstrate the obvious inconsistencies in computed ground response as a result of different assumptions made on the transmitting boundary for the site. The cause of these inconsistencies in computed response is the departure from the ideal assumption that the soil deposit below the transmitting boundary is a linear elastic and homogeneous half‐space. It is shown that under low‐intensity shaking, multiple reflections from the discontinuities below the boundary can be significant, and under strong shaking, nonlinear soil response can alter the wave form, as well as reduce the intensity of the motion. Either situation makes correlation between the input motion at the boundary and the control outcrop motion uncertain. For seismic response analyses of sites underlain by very thick soil deposits, it is suggested that consideration also be given to the shear strength profile at the site when deciding on the location of a transmitting boundary.

A theory of viscoplasticity for frictional materials is developed in which first and third invariants of stress and strain are used instead of the more conventional second invariants. Rate effects are incorporated directly into the expression for the flow surface so that the numerical algorithm for a plasticity subroutine can be used. The usual concepts of strain‐ and strain rate‐hardening viscoplasticity are used, except that a non‐associated flow rule is required to control dilatation. For two sandy materials, detailed comparisons are made of theoretical and experimental stress‐strain data for both static and dynamic paths.

An analytical solution is presented for the flow field around cones penetrating an inviscid and incompressible fluid. The stream function, velocity field, and strain rates around 18° and 60° cones advancing at a rate of 2 cm/sec are fully determined and presented. It is assumed that this strain rate field will give the first approximation to the in situ strains during penetration of very soft cohesive soils.

Vibro‐replacement stone columns were used to support a large wastewater treatment plant founded on up to 48 ft (15 m) of soft estuarine deposits. Support was required for distributed foundation stresses up to 3,000 psf (145 kPa). The basic design requirement was a loading of 30 tons (265 kN)/stone column with a settlement of less than 0.25 in. (6 mm) under that load in a test on a single column within a group. Column spacings ranged from a $4\mathrm{ft}\times 5\mathrm{ft}$ (1.2 m by 1.5 m) pattern under the most heavily loaded areas, to a $7\mathrm{ft}\times 7\mathrm{ft}$ (2.1 m by 2.1 m) pattern under lightly loaded areas. Twenty‐eight single column load tests were done during the installation of the 6,500 stone columns to evaluate load‐settlement behavior. Laboratory tests were done to provide soil property data needed for finite element predictions of both the load test behavior and settlements of the completed structures. Predicted load test settlements were somewhat greater than those recorded during the load tests, but agreement was generally good. The installation of stone columns led to a reduction in settlements to about 30–40% of the values to be expected on unimproved ground. The settlement of a large uniformly loaded area of improved ground was predicted to be about ten times that measured in a load test on a single column within the area. Measured settlements varied from 1.0–2.4 in. (25–60 mm) for a soft sediment thickness of 32–35 ft (10–11 m). A settlement of about 2.5 in. (64 mm) was predicted by the finite element analysis. Settlement predictions using other, simpler methods gave values which agreed reasonably with both the measured values and the finite element predictions.

Relaxation, defined as a decrease in bearing capacity of driven piles with time after initial driving, has been observed to be a rare phenomenon in southern Canadian geotechnical conditions. It has been encountered by the writers with piles driven to end bearing in shale of the Georgian Bay Formation in the Bayfront area of downtown Toronto, Ontario. In this case, the approach of increasing the end area of the piles to reduce the bearing pressure has been counter‐productive. In other founding conditions, a reduction in driving resistance between the end of initial driving and the beginning of redrive has not indicated a reduction in bearing capacity, but rather an increase in the developed force from the pile hammer. It appears to be primarily associated with the use of single‐acting diesel hammers.

The analysis of the stability of slopes using limit equilibrium methods usually requires the determination of the critical failure surface having the minimal factor of safety. This paper presents an optimization technique, adapted from operations research, to determine both the minimal factor of safety and the associated critical failure surface. The technique treats the factor of safety as an optimal function of the N geometrical coordinates defining potential admissible failure surfaces, and searches for the optimum by a reflection algorithm through an N‐dimensional space defined by these geometrical coordinates. Application of the technique, as illustrated by examples, revealed that in comparison with the popularly known grid search method, the technique yields lower values of the minimal factor of safety for fewer computations, and is suitable for virtually all types of failure surfaces.