Experimental Study On Mechanical Properties Of Clay Mixed With Gravel

Gravel clay is widely distributed in nature and also used widely in engineering. For example, it can be used for core embankment of impervious core wall materials and road roadbed filler. However, the variation of mechanical properties with gravel and other factors are not yet very clear. This paper conducts compaction test, static triaxial test and compression test to analyze the amount of gravel used and other influential factors of compaction capacity, shear strength and compressive property. The main contents are as follows:1) Through different gravel amounts of gravel clay indoor compaction test, it analyzes the various influential factors of compaction test results and find the relationship between the gravel amount, maximum dry density and optimum moisture content. Draw the conclution that with the increase of the gravel amount, optimum moisture content decreases and the dry density increases. The result is mainly because that the compaction degree of the clay used in gravel clay is less than pure clay, so the theoretical value is different from the actual value.2) It analyzes the influence of gravel amount of gravel clay to unconfined compressive strength. With the increase of the amount of gravel, unconfined compressive strength decreased roughly, and when the amount of gravel used is larger, unconfined compressive strength decreased more significantly. This shows that gravel clay’s unconfined compressive strength mainly depends on the state of the clay.3) This paper carries out static triaxial tests to study the influence of different gravel amount, gravel shape and gravel diameter to the shear performance of gravel clay, and analyze the principal stress difference variation with axial strain in detail. It finds that there is a clear relationship between the confining pressure, gravel amount and failure strength. When the confining pressure is small, with the increase of the amount of gravel, the shear strength decreases to the minimum firstly and then increases gradually. When the confining pressure is large, the shear strength increases with the gravel amount, this is mainly because gravel clay is relatively dense after consolidation.4) This paper carries out laboratory compression test to gravel clay and analyzes the relationship between compression index and gravel amount. Draw the conclusion that a critical value of gravel amount is exist between 20% and 30%. When gravel amount is smaller than the critical value,compression index becomes larger with the increase of gravel amount. However, when gravel amount is larger than the critical value,compression index (within the test range) decreased with the increase of gravel amount. That is because gravel gradually form the framework of soil.