Effect of Grain Size and Distribution on Permeability and Mechanical Behavior of Acrylamide Grouted Sand

In order to investigate the effects of grain size and distribution of sand on the mechanical properties and permeability of grouted sands, several gradations of sands were grouted using acrylamide chemical grout and tested. The influence of sand density, fines content [particle size $<0.075\mathrm{mm}\left(0.0029\mathrm{in.}\right)$ ], curing condition and time, and grout dilution were investigated. Groutability of sand with various fines content was investigated using injection pressure up to $138\mathrm{kPa}\left(20\mathrm{psi}\right)$ , equivalent to injection hydraulic gradient of 155. From the groutability study a relationship between grouting pressure and fines content have been developed. Grouted sand specimens were cured in moist, submerged in water and dry (air cured) conditions for 3, 7, and $28\text{days}$ and tested. The stress–strain relationships were developed to characterize effect of curing condition and curing time on the mechanical behavior of acrylamide grouted sands. The grout was diluted with water up to 50% and its effect on grouted sand mechanical properties and permeability behavior was studied. Permeability of grouted sands was measured using constant head permeability tests over a period of $120\text{days}$ . Based on the test results, relationship between unconfined compressive strength and permeability of acrylamide-grouted sand was investigated. Particle size distribution and fines content influenced the strength, modulus and stress-strain relationship but had minimal effect on the failure strain and permeability of grouted sand. Grouted sand strength varied from $290\mathrm{kPa}\left(42\mathrm{psi}\right)\text{to}820\mathrm{kPa}\left(119\mathrm{psi}\right)$ . The behavior of acrylamide grouted sand was analyzed based on the test variables and quantified using simple mathematical relationships.