This paper presents a laboratory investigation into passive stabilisation of liquefiable sands by means of colloidal silica (CS). In order to examine the improvement of the mechanical behaviour of liquefiable sands stabilised with CS, an extensive laboratory testing programme comprising unconfined compressive strength and Brazilian tensile strength tests, as well as undrained monotonic and cyclic triaxial tests, was performed on a clean quartz sand treated with CS. The test results are compared to the corresponding results for the untreated sand. The effects of CS concentration, curing time, density and confining stress on the monotonic and cyclic response of the treated sand are examined, among others. It is shown that stabilisation of the tested sand with CS significantly improves both the undrained monotonic and cyclic strength. The influence of CS concentration on the monotonic response is reduced with increasing mean effective stress. Cyclic resistance, however, is shown to be practically unaffected by CS concentration. Furthermore, cyclic straining at 5 to 10% of double-amplitude axial strain does not influence the undrained shear strength of the stabilised sand.

This paper presents a laboratory investigation into the mechanical response of a silty sand, with a fines content of 10%, stabilized with colloidal silica (CS). To this end, a series of unconfined compression tests as well as monotonic and cyclic triaxial tests was performed on a silty sand, comprising a mixture of a clean sand and a silty sand, stabilized with two concentrations of CS. The effect of various parameters on the behaviour of the stabilized silty sand was studied, such as CS concentration, soil density, and the presence of fines. The test results were compared with the corresponding of the untreated silty sand as well as the parent clean sand. It is shown that stabilization, even at the lowest CS = 6% concentration studied, significantly improves the undrained shear strength as well as the liquefaction resistance of the stabilized silty sand. Both the monotonic and cyclic response of the stabilized soil are only slightly affected by density. Furthermore, cyclic straining up to at least 5% of double-amplitude axial strain does not influence the undrained shear strength of the stabilized silty sand.

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The Greek economic crisis of 2009 onwards has affected all aspects of social and economic life of the country, including transportation. The present study focuses on the impact of economic crisis on the long distance transportation between the island of Crete in Greece, the largest Greek island and one of the largest in the Mediterranean Sea, and the Greek mainland. A questionnaire survey was used to investigate the opinions of the Cretans on the way the economic crisis influenced their transportation to the Greek mainland. The results of the survey show that the frequency of the Cretans’ travels was significantly limited, owing to the increased direct or indirect associated cost, due to the economic crisis. Especially for those who struggled to make ends meet, the transportation to the mainland dropped to the bare essentials. Furthermore, the respondents deemed that the deregulation of the Greek maritime and airline markets was also to blame for the high fares, thus they favoured a regulated public transport sector and were against privatization. Inevitably, financially vulnerable individuals were the most preoccupied with these issues. A feeling of isolation and exclusion was revealed by the sample on occasions when the scheduled trips were cancelled by the operators due to exogenous parameters.