A Review of the Sand Castle Test for Assessing Collapsibility of Filters in Dams

The Sand Castle (SC) test is a simple test for recognition of collapsibility and self-healing in filter materials. The rather qualitative outcomes and dissimilar techniques implemented in conducting the test complicate judgment about filter performance from the viewpoint of crack-holding propensity. This paper reviews earlier research concerning SC testing and highlights its governing principles. Results of comprehensive SC tests with different methodologies are presented, and the role of various parameters in results of SC tests is elaborated. The influence of basic soil properties (such as water content, relative density, fines content, and plasticity of the fines) on the ability of filters to hold a crack are assessed. Recommendations for appropriate conduct of SC tests and acceptance criteria in relation to field performance are provided.