This paper summarizes the state of the art for in situ conductivity testing of compacted clay soils. Nine methods of testing are reviewed: (1) The Boutwell permeameter; (2) constant‐head borehole permeameters, e.g., the Guelph permeameter; (3) porous probes, e.g., the BAT device; (4) open, single‐ring infiltrometers; (5) open, double‐ring infiltrometers; (6) closed, single‐ring infiltrometers, (7) sealed, double‐ring infiltrometers; (8) the air‐entry permeameter; and (9) lysimeter pans. Installation procedures are given, equations for calculating hydraulic conductivity are presented, simplifying assumptions are listed, and case histories are reviewed. Each type of permeameter has advantages. The Boutwell permeameter is especially convenient for measurement of the vertical and horizontal hydraulic conductivity. Borehole permeameters and porous probes provide data relatively quickly but permeate a relatively small volume of soil. Of the permeameters that can permeate large volume of soil, the sealed double‐ring infiltrometer and pan lysimeter are the most versatile.

A simplified mathematical model of the coupled horizontal and rocking vibration of an embedded foundation is presented based on the Baranov‐Novak method. Using the concept of additional moment introduced in this model, the displacement formulas for an embedded foundation can be expressed by four parameters instead of the six parameters in Novak's model. This makes it possible to determine the vibrational parameters as an inverse problem from the measured dynamic response for embedded foundation. So the parametric study for embedded foundation is facilitated by the simplified model. Dynamic experiments of the foundation with different depths of embedment are conducted, and compared with the results of this study and those of Novak's and Whitman's methods.

Sensitivity magnitudes are interpreted from remolded strength values in recent subsurface geologic, geotechnical, and geochemical data from the Bootlegger Cove Formation adjacent to the Turnagain Heights Landslide. The results show that strata composed of highly sensitive clays occur in both the middle and lower zones of the formation, and that between these strata the clays are generally of low‐to‐medium sensitivity. The most sensitive stratum is in the middle zone between two sand layers, and its sensitivity increases from both clay‐sand interfaces to a maximum at the center of the stratum. The pore fluid chemistry of the highly sensitive materials differs from that in the materials of low to medium sensitivity only in their concentrations of organic carbon, chloride, bicarbonate, and sulfate. The total dissolved solids concentration is low, and the ratio of monovalent to divalent cations is very high throughout the middle and lower zones of the formation. Of the known causes of high and extremely high sensitivities, only organic and/or anionic dispersants are consistent with these findings.

Compacted soils wetted under load can both swell and collapse (subside) depending on their condition and the magnitude of the vertical overburden stress. One‐dimensional compression tests were conducted to clarify the influences of compaction method, compaction water content, relative compaction, vertical stress level, and load‐wetting sequence on post‐compaction wetting‐induced volume changes in a moderately plastic clayey sand. Compaction method and load‐wet sequence had only a minor effect on wetting‐induced collapse. The double‐odometer test was judged to be sufficiently accurate for use in evaluating wetting‐induced collapse. Both swelling and collapse were reduced or eliminated by compacting the soil at water contents on the wet side of the line of optimums for impact compaction. Collapse, but not swelling, could also be reduced by compacting the soil to high levels of relative compaction. By plotting isograms of volume changes in the compaction water content‐relative compaction space, combinations resulting in no wetting‐induced volume change were identified for various vertical stress levels corresponding to the values existing in large fills and embankments.

Equations for seismic ray‐path curvature are presented for both linear and nonlinear velocity versus depth models. Techniques are then developed for correcting cross‐hole results for ray‐path curvature and for determining the model constants for seismic refraction based on data from two source‐to‐receiver spacings. The principal advantage of the techniques is that corrections are independent of the soil properties and stress conditions above and below the test elevation, not including the relatively thin zone through which the ray path passes. The linear model is of the form $V=V_o+\mathrm{mz}\text{,}$ where $V_o$ and m are constants to be determined. Since the propagation velocity function needs only to be linear in the thin zone through which the ray path passes, this model is valid in many situations. The nonlinear model, $V=a(z+z_o{)}^b\text{,}$ has three unknowns, a, $z_o\text{,}$ and b. Since two receiver locations will only provide sufficient information to solve uniquely for two unknowns, an assumption for the third constant must be made. If $z_o=0$ is assumed, the model becomes useful for refraction studies in cohesionless soil. If $b=1/4$ is assumed, cross‐hole test results in shallow, normally consolidated, uncemented sand can be corrected.

Smith developed a wave equation method by idealizing a pile‐soil system as a series of masses and springs for the analyses of complicated pile driving problems. The soil parameters used in this method were proposed on the basis of his experience in piling practice and hence, were recognized to be relatively crude from soil mechanics aspects. This paper presents results of an analytical procedure for determining the shaft damping parameter and relating it to the soil properties: (1) Shear modulus; and (2) shear strength. A dynamic finite element computer program is developed to analyze the pile shaft resistance by using an elasto‐plastic approach; the relationship between the shaft damping parameter and the other parameters such as pile penetration velocity, radius of yielding zone, and force pulse duration time are also examined. It is found that the Smith damping parameter cannot be back‐calculated to be some simple constant.

Stiff clays and shales forming part of natural slopes and earth dams contain fissures in their structure. Very little is known about the effect that fissure parameters such as orientation, length, number of fissures, and their mode of arrangement have on the unconfined compressive strength of stiff clays and shales. This study reports laboratory investigations designed to understand the effect that such fissure parameters have on the unconfined compressive strength of stiff fissured clays. To this end, prismatic samples of brittle kaolinite clay with preexisting cracks are tested in the laboratory under uniaxial compressive stress conditions. It is found that the orientation, length, number, and arrangement of cracks in a clay sample has a marked influence on its unconfined compressive strength. The laboratory results indicate that: (1) There is a critical crack orientation in a sample at which the uniaxial compressive strength reaches a minimum value; (2) the longer the length of a crack or the larger the number of cracks in a sample, the lower is its confined compressive strength; and (3) samples with cracks arranged in a leftstepping manner are weaker in compression than samples containing right‐stepping cracks.

It is shown that the single closed-form expression, ☌_h = k_wYH β - 2 (1 - H/Z)- (1 - H/Z)_β-9 where β=K₁/tanγ, models the pressure distribution behind rigid rough retaining structures inactive and passive failure modes under translation, rotation about the base, and rotation about the top. Each condition is represented by two condition specific parameters in the expression. These are K_w, the coefficient of lateral earth pressure at the wall interface, and a, a shape parameter representing the size of the region failed soil behind the wall. For translating walls, K_w is given by K_w=tan₂θ + k/1 + Ktan²θ and β is approximated by βw=K_wcos²θ/ (cos δ)^1/2 ± [sin (θ+δ) sinθ]^1/2. Further investigations of these parameters are necessary for rotating walls.

Results of an experimental investigation into the bearing-capacity aspects of reinforced cohesive soils are presented. Undrained model tests are carried out on strip footings on unreinforced and reinforced cohesive soil. The reinforcements are in the form of ties that have been cut out from household aluminum foil. The reinforcement ties are placed only in the direction normal to the longitudinal axis of the footing. In this study, the length of the reinforcing ties and the spacing between them is varied. It is observed that the bearing capacity of the strip footing on reinforced cohesive soil is affected more by the spacing between the reinforcing ties than by the length of the ties. Overall, an increase in the bearing capacity of reinforced cohesive soils is found and compared to unreinforced cohesive soils. Finally the failure mechanism of reinforced cohesive soils under strip footing has been discussed. Different failure modes based on the density of reinforcements have been identified.

A closed-form solution for a rigid-plastic soil penetration function is used to qualitatively investigate the energy transmission characteristics of the Standard Penetration test. It is shown that the percentage of the impact energy used to advance the sampler decreases with an increase in blow count, and that for low blow counts several penetration cycles are required to transmit the energy to the sampler. The results obtained are compared with those for an elasto-plastic soil penetration function, assuming an elastic soil compression of 2 mm for all blow counts.