Influence of organic matter content, moisture status and time after reworking on soil shear strength

SUMMARY Recovery of soil shear strength was measured in disturbed samples of a calcareous clay loam soils, with four different organic matter contents. Repacked soil cores were put on tension tables at 25 or 50 cm water tension. Shear strength and water content were measured at one of eight time intervals, from 48 h to 7 weeks after the tension was applied. Soil strength increased with increasing organic matter content or increasing the applied tension. The major factor affecting strength, however, was the length of time that tension was applied. Because water contents showed little or no change with time on the tension table these results demonstrate thixotropic recovery of shear strength. This property is discussed with relevance to the soil's potential for mole drainage.