Strain-Rate Selection in the Constant-Rate-of-Strain Consolidation Test

Constant-rate-of-strain (CRS) consolidation tests were performed on remolded kaolinite specimens. The effect of strain rate on CRS test data is shown. A relation between soil parameters and strain rate was developed and used to formulate a strain-rate selection procedure. The fmal selectlon procedure is based on liquid limit and initial degree of saturation of the specimen and is presented in graphical form. The procedure is applicable to all types of soils

Constant-Rate-of-Strain and Controlled-Gradient Consolidation Testing

Controlled-gradient (CG), constant-rate-of-strain (CRS), and conventional incremental-loading (STD) consolidation testing are compared and evaluated. Undisturbed samples representing three soils common to Kentucky were used in the testing program. Settlements estimated by each testing technique were compared with settlement records from one of the sites. Results of 15 CG, 14 CRS, and 32 STD consolidation tests are shown. No significant differences were noted in values obtained from the three types of consolidation tests. Feasibility of the new test methods for routine testing is briefly discussed and recommendations were made for refinements in testing procedures

Analysis of Time-Independent Consolidation Data

The one-dimensional laboratory consolidation test developed by Terzaghi permits deformation and drainage only in the vertical direction. The stress-strain characteristics of data obtained from this test are normally studied using a semilogarithmic graphical representation, that is, vertical strain or void ratio is plotted as a function of the logarithm of effective stress. Such a representation permits an analysis of the stress history and compressibility characteristics of soils. Knowledge of these material characteristics is of great practical value in the prediction of settlement associated with loading where the effects of lateral consolidation may be neglected

Shear Strength of Cohesive Soils and Friction Sleeve Resistance

Cone penetrations tests were performed on the silty clays of Kentucky, U.S.A., using a boring rig to push the Dutch, friction sleeve, cone penetrometer. Thin-walled tube samples were taken from nearby boreholes. For the first four sites, unconfined compression tests and unconsolidated-undrained triaxial test were performed on the samples. For the last four sites, consolidated-undrained triaxial tests were performed on the samples. A procedure for estimating in situ shear strength from triaxial test stress paths was developed. Small rock fragments in these residual soils caused erratic cone resistance at many locations. As a result, the friction sleeve resistance provided the best correlation with in situ shear strength. In situ shear strength was found to be approximately 80 percent of the friction sleeve resistance, which confirms the findings of others

In Situ Shear Strength Parameters by Dutch Cone Penetration Tests

Dutch cone penetration testing was performed and undisturbed samples were collected at four Kentucky highway sites. Shear strength, as determined by consolidated, undrained triaxial testing of the undisturbed samples, was correlated with friction resistance as measured by the Dutch friction cone. Statistical analysis of all data showed shear strength to be about 80 percent of friction resistance. Recommendations for the use of the Dutch cone penetration test in Kentucky soils were also made

Orbital assembly and maintenance study

The requirements, conceptual design, tradeoffs, procedures, and techniques for orbital assembly of the support structure of the microwave power transmission system and the radio astronomy telescope are described. Thermal and stress analyses, packaging, alignment, and subsystems requirements are included along with manned vs. automated and transportation tradeoffs. Technical and operational concepts for the manned and automated maintenance of satellites were investigated and further developed results are presented

Orbital assembly and maintenance study. Executive summary

A sound, practical approach for the assembly and maintenance of very large structures in space is presented. The methods and approaches for assembling two large structures are examined. The maintenance objectives include the investigation of methods to maintain five geosynchronous satellites. The two assembly examples are a 200-meter-diameter radio astronomy telescope and a 1,000-meter-diameter microwave power transmission system. The radio astronomy telescope operates at an 8,000-mile altitude and receives RF signals from space. The microwave power transmission system is part of a solar power satellite that will be used to transmit converted solar energy to microwave ground receivers. Illustrations are included

Constant-Rate-of-Strain and Controlled-Gradient Consolidation Testing

Controlled-gradient (CG), constant-rate-of-strain (CRS), and conventional incremental-loading (STD) consolidation testing are compared and evaluated. Undisturbed samples of tbree soils common to Kentucky were used in the testing program. Results of 15 CG, 14 CRS, and 32 STD consolidation tests are evaluated. Feasibility of the new test methods for routine testing is briefly discussed and recommendations are made for refinements in testing procedures

Feral swine \u3ci\u3eSus scrofa\u3c/i\u3e: a new threat to the remaining breeding wetlands of the Vulnerable reticulated flatwoods salamander \u3ci\u3eAmbystoma bishopi\u3c/i\u3e

Feral swine Sus scrofa have been implicated as a major threat to sensitive habitats and ecosystems as well as threatened wildlife. Nevertheless, direct and indirect impacts on threatened species (especially small, fossorial species) are not well documented. The decline of the U.S. federally endangered reticulated flatwoods salamander Ambystoma bishopi, categorized as Vulnerable on the IUCN Red List, has been rapid and there are few remaining breeding locations for this species. The flatwoods salamander depends on complex herbaceous vegetation in all life stages, including eggs, larvae and adults. Historically sets of hog tracks have been observed only occasionally in the vicinity of monitored reticulated flatwoods salamander breeding wetlands, and damage to the wetlands had never been recorded. However, during the autumn–winter breeding season of 2013-2014 we observed a large increase in hog sign, including extensive rooting damage, in known flatwoods salamander breeding wetlands. Our objective was to assess the amount of hog sign and damage in these wetlands and to take corrective management actions to curb additional impacts. Of 28 wetlands surveyed for hog sign, presence was recorded at 68%, and damage at 54%. Of the 11 sites known to be occupied by flatwoods salamanders in 2013-2014, 64% had presence, and 55% had damage. We found that regular monitoring of disturbance in wetland habitats was a valuable tool to determine when intervention was needed and to assess the effectiveness of intervention. Habitat damage caused by feral hogs poses a potentially serious threat to the salamanders, which needs to be mitigated using methods to control and exclude hogs from this sensitive habitat