Time‐independent analyses of five of ten zones of a dummy reinforced concrete pipe at Cross Canyon are presented. All five zones are characterized by “positive projection,” four in a narrow, vertical‐sided trench with a projection ratio of about 0.4, one, almost fully projecting. Two zones (1 and 4) were surmounted by ordinary embankment material, three entrenched zones (8, 9 and 10), by low modulus embankment inclusions (polystyrene plank, uncompacted soil, and baled straw). Each zone was heavily instrumented for assessment of peripheral soil pressures, internal strains, and wall displacements. Fluid settlement platforms and additional stressmeters were placed in the embankment. Instruments were monitored at frequent increments of overfill. A finite element code, REA, (for Reinforced Earth Analysis) was adapted to special needs of pipe and boundary geometry and nonlinear, incremental, embankment construction. Correlations were established between finite element results and certain parameters obtained from extensive instrumentation at Zones 1, 4, 8, 9 and 10. Initial analyses employed asymmetrical boundaries determined by presurveying canyon cross‐sections. Additional analyses compared finite element results obtained with a more economical, symmetrical mesh.

A well planned and carefully executed program of oedometer tests on high quality undisturbed samples is shown to provide considerable practical information about the soil properties of a natural, very stiff clay deposit. The effects of sample disturbance and type of oedometer on the preconsolidation stress are shown. A special long‐term oedometer test verified earlier results that $K_0$ is practically constant during secondary compression. Destructuration due to a single unload‐reload cycle caused a significant decrease in the coefficient of secondary compression. The practical implications of these test results are also examined.

Underground excavated openings in permafrost can have significant ground stability problems if the thermal regime of the area is disturbed. Other factors influencing ground stability besides temperature variation include dimensions of the excavation, thickness of the overburden, and geometry of the opening. This paper summarizes the results of a research project conducted at the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) permafrost tunnel. The relationships between the ground temperature, the roof span dimensions, and the vertical convergence rate of the CRREL tunnel correlates with a combined exponential and logarithmic model. The continuous deformation of the tunnel is primarily temperature dependent. In addition to the effect of temperature, the opening width also exhibits a strong influence on tunnel deformation. The span length gradually achieved a constant effect upon tunnel deformation as the opening width increased. The overburden thickness also exhibits an influence on convergence rate.

A new test, called the seismic cone penetration test (SCPT) is described. A small rugged velocity seismometer has been incorporated into an electronic cone penetrometer. The combination of the seismic downhole method and the CPT logging provide an extremely rapid, reliable, and economic means of determining stratigraphic strength and modulus information in one sounding. Results using the seismic cone penetration test are presented and compared to conventional in situ techniques.

Triaxial compression tests were run to compare the stress‐strain response of a sand reinforced with continuous, oriented fabric layers as opposed to randomly distributed, discrete fibers. The influence of various test parameters such as amount of reinforcement, confining stress, and inclusion modulus and surface friction were also investigated. Test results showed that both types of reinforcement improved strength, increased the axial strain at failure, and in most cases reduced post‐peak loss of strength. At very low strains $(<1\%)$ fabric inclusions resulted in a loss of compressive stiffness. This effect was not observed in the case of fiber reinforcement. The existence of a critical confining stress was common to both systems. Failure envelopes for reinforced sand paralleled the unreinforced envelope above this stress. Strength increase was generally proportional to the amount of reinforcement, i.e., the number of fabric layers or weight fraction of fibers, up to some limiting content. Thereafter, the strength increase approached an asymptotic upper limit. Fiber‐reinforced samples failed along a classic planar shear plane, whereas fabric‐reinforced sand failed by bulging between layers.

A fine-grained soil was mixed with 1% by volume of 20-mm-long synthetic fibers. Laboratory specimens were compacted at various water contents and tested in unconfined compression. Specimens compacted wet of optimum were found to have somewhat greater strength (up to 25%) and strain to failure with fibers in comparison with specimens without fibers. Dry of optimum, there was little or no benefit from the fibers. Nylon and polypropylene fibers gave similar results. Mixing the fiber into the soil was difficult; especially for the smaller (less than 0.20 mm diameter) fibers.