Accession Number : AD0824882

Title :   TRAFFICABILITY PREDICTIONS IN TROPICAL SOILS. REPT. 5. COSTA RICA STUDY NO. 1 (JANUARY 1963-JANUARY 1965),

Corporate Author : ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS

Personal Author(s) : McDaniel, Alvin R.

Report Date : DEC 1967

Pagination or Media Count : 103

Abstract : Soil trafficability studies have shown that the strength of a soil is of major importance to vehicle mobility and varies principally with soil moisture; therefore, a means of predicting moisture content of a soil is essential to the forecasting of soil trafficability. The U. S. Army Engineer Waterways Experiment Station (WES) soil-moisture prediction method for United States soils was applied to sites in Costa Rica to determine whether the method was applicable for the prediction of moisture content of tropical soils. Data necessary for the predictions were collected on five sites in the Premontane wet climate of the Reventazon Valley at Turrialba, Costa Rica. Changes in soil moisture content, density, strength, and remolding strength with changes in weather conditions were investigated at regular intervals for 25 months. These data were analyzed and used to predict soil-moisture content and to establish the relation between moisture content and soil strength. The analysis shows that the WES method is applicable to prediction of soil-moisture content at the five sites in Costa Rica. Groundwater did not have an appreciable influence on soil-moisture depletion since drainage from the 0- to 12-in. (0- to 30.5-cm) soil layer was related directly to rainfall. Topography was shown to influence soil-moisture content to some degree. Analysis of strength data showed a highly significant relation between soil strength and moisture content. On the basis of rating cone index, the trafficability of the soils was considered poor during the wet season and good during the latter part of the dry season. Basic data and photographs for each test site are included. (Author)

Descriptors :   (*TRAFFICABILITY, SOILS), (*SOILS, TROPICAL REGIONS), ROADS, PLANNING, SOIL MECHANICS, MOBILITY, TROPICAL TESTS, COSTA RICA, PREDICTIONS, MOISTURE.

Subject Categories : Soil Mechanics
      Civil Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE