ABSTRACT
This paper introduces a new methodology and machinery to extract soil properties and assess its liquefaction susceptibility. A mechanical Gouda tip cone penetrometer is used to apply a cyclic load on the soils. This test aims a load closer to real world liquefaction events, more robustness and a cheaper cost than a conventional CPTu. Since the cone tip used for the test does not have a pore pressure sensor, nor a friction sleeve and electrical or optical cables, it is of low maintenance, easy to operate and can be used to drill through gravel or any dense layer to reach layers of interest without digging a borehole, saving time and money. The liquefaction resistance is found using the response of soils to cyclic loading on the cone tip. The methodology also involves measuring the change of tip resistance before and after applying a cyclic load and correlates it to the volume changes that took place during it. For this, an experimental campaign was carried out in a new calibration chamber using a mini cone with stress and pore pressure changes measured independently in the soil during the cyclic load. The different response to cyclic load of clean Fontainebleu GA39 sand under different vertical stresses, saturation conditions and created by different sample preparation methods is studied. In turn, the pore pressure increase and the corresponding number of cycles during the cyclic cone penetration tests are compared with similar results from cyclic compressive triaxial tests. This allows us to find a relation between the loading applied in the two methods to cause a similar increase of pore pressure. Hence, a method is suggested to compare the loading applied by the cone penetrometer to the Cyclic Stress Ratio(CSR) expected in a liquefaction event. Eventually, using the CSR and CRR defined, the liquefaction susceptibility of the soils can be calculated.
