A test section was established next to a 40‐ft‐deep, braced excavation in soft to medium‐stiff, saturated clays in Chicago, Ill. Surface and subsurface three‐dimensional ground movements, pore water pressures, sheet‐pile deformations and strut loads were measured. Results of these observations were correlated with construction activities at the test section. Larger than expected ground‐surface settlements adjacent to the excavation were observed. The large movements occurred as a result of overexcavation during construction. The largest incremental ground movements occurred when the excavation was approximately half completed. Base stability computations indicated that the factor of safety against basal heave at that point in construction was 1.1. Two distinct shear zones developed in the soil mass; their initiation corresponded to the times when the largest incremental movements occurred. Soil displacements were always directed towards the excavation with magnitudes, at later stages of construction, larger than those measured on the sheet pile. Pore water response was markedly influenced by sheetpile installation and strut preloading; as a result, little net change in pore pressures was observed at the end of construction. Magnitudes of measured strut loads were within the levels expected, based on standard design procedures.

Strain fields that arose at various times during construction of a braced excavation through soft to medium‐stiff saturated clays in Chicago are presented. Pile driving induced largely horizontal compressive strains and positive excess porewater pressures within the adjacent clay. These effects tend to reduce the passive resistance provided by the soil between the sheet‐pile walls and promote movements below the excavated grade at any early stage of excavation. The strains computed from data taken, during excavation indicated that strains localized in distinct zones twice during construction. This phenomenon was associated with movements below the base of the excavation and with large increases in measured strut loads. The in situ response at the test section implies that strain‐softening phenomena occurred within the lightly overconsolidated, saturated clay during excavation and bracing.

The study of skin friction developed in the present article falls within the scope of research work on high‐frequency vibro‐piling (1,500 to 3,000 Hz). Our laboratory measurements performed thus far have concerned the general behavior of the test unit without dissociating point force and skin friction. Previous studies have indicated that vibro‐piling is only possible when an excitation frequency is used equal to one of the frequencies characteristic of the system. A more refined analysis of the phenomena involved depends on determination of the skin friction coefficient which was measured in our laboratory using a horizontal test bench. It was thus shown that this friction coefficient is a decreasing function of the power transmitted by the exciter to the sheet pile: it is directly related to the depth of penetration of the sheet pile into the sand; and it is independent of the forward movement velocity of the sheet pile without excitation but increases with this velocity in the presence of excitation, thereby enabling reconstruction of a vibro‐driving curve to provide satisfactory estimation of refusal.

Cementation can exist in a sand naturally or it can be added artificially. In either case, it is known to increase the resistance of a sand to liquefaction, and can be a critical factor in engineering decisions about site response, This investigation involves testing of weakly cemented sands which have a range of cementation levels and unit weights. Both triaxial and cubical cyclic shear devices are used in the testing. The cubical shear apparatus is used to allow assessment of possible stress concentration effects in the triaxial device, and to investigate loading under multiaxial stress conditions. The experimental results are used to separate the effects of unit weight and cementation, and to define the conditions where cementation begins to override the influence of unit weight.

Since the late 1950s solid waste incinerators have become widely used in the United States. The incineration of solid waste produces large quantities of bottom and fly ash, which has been disposed of primarily by landfilling. However, as landfills become undesirable other disposal methods are being sought. An experimental research program is conducted to determine engineering properties of solid waste incinerator fly ash (SWIF) in order to evaluate the feasibility of using the material for compacted fill and road and subbase construction. Moisture‐density relationship, permeability, shear strength, and California bearing ratio (CBR) are investigated. The effects of densification on these engineering properties are also examined. In addition, the effectiveness of cement and lime stabilization is investigated using two common mix ratios. Test results of stabilized mixes are compared to the unstabilized material. Cement stabilization is found to be very effective in reducing permeability, and increasing shear strength and CBR values of the material. The results indicate that SWIF with cement stabilization may be used effectively for compacted fill and road subbase construction. Finally, some environmental aspects related to these applications are examined.

A series of direct shear laboratory tests was performed in order to examine the mechanism of shear zone development in reinforced sands and to quantify their deformation characteristics. Six types of reinforcements were used to evaluate the effects of reinforcement concentration, stiffness, and reinforcement‐soil bond strength on the deformation and strength of reinforced sands. Tests results show that shear zones tend to be wider in reinforced soil composites than in soil alone. The width of the shear zones increases with increasing stiffness of the composite due to any combination of increased reinforcement concentration, stiffness, and reinforcement‐soil bond strength. A linear relationship between reinforcement concentration and increased strength is not observed.

Clay liners have been used as a means of leachate containment at landfills in Wisconsin for over 10 years. Many of these liners are 1.22–1.52‐m (4–5‐ft) thick and their construction is well documented. Since 1980, the Wisconsin Department of Natural Resources has required “collection basin lysimeters” to be installed at most clay‐lined sites to measure the quality and quantity of leakage from a discrete portion of the liner. These devices were initially required to provide a method for monitoring soil moisture in the unsaturated zone beneath the clay liners because in most cases suction lysimeters had not functioned properly. More recently, volume measurements from regularly sampled lysimeters have been used to estimate field hydraulic conductivity of clay liners. Field hydraulic conductivities calculated from the measured rate of seepage into eight separate lysimeters at three operating landfills is always less than $1\times {10}^{-7}\mathrm{cm}/s\text{.}$

A boundary element method is presented for the ``back analysis'' of convergence measurements and measurements of the stress tangential to the tunnel circumference in an unlined tunnel following its excavation. When measurements are made of tunnel convergence between three points on the tunnel circumference and tangential stress at two points on the tunnel circumference, this method enables estimates to be made of (1); The modulus of elasticity of the rock mass; (2) the Poisson's ratio of the rock mass; and (3) the initial stress field in the vicinity of the tunnel.