STRENGTH AND COMPRESSIBILITY OF ABQAIQ MARL, SAUDI-ARABIA

The increasing number of construction projects and the lack of good qu ality soil for use in these projects in eastern Saudi Arabia necessita te the use of available marginal soils. Most, if not all, engineering projects use the fine-grained calcareous sediments, known locally as m arl, either as a foundation material or as a fill material. The lack o f published information on their engineering characteristics and behav ior under ambient conditions have resulted in many construction and po st-construction problems. This investigation is one of a series to eva luate the geotechnical properties of selected marl soils obtained from different areas in eastern Saudi Arabia. Marl samples, obtained from Abqaiq, were prepared in the laboratory under controlled conditions an d subjected to different tests including CBR (soaked and unsoaked), tr iaxial compression, unconfined compression and one-dimensional compres sion tests. Samples were prepared at different moisture contents on bo th the wet and dry sides of optimum. X-ray diffraction analysis indica tes that this marl contains high percentages of dolomite and calcite, in addition to other materials. The molding water content significantl y affects the engineering properties of this material. Compaction on t he dry side of optimum resulted in samples that have some swelling pot ential and highly compressible characteristics when subjected to a loa d after inundation.