Experimental Study On The Relations Between Acoustic Velocity With Physical And Mechanical Properties Of Seabed Sediments

Drilling operations in Deepwater,usually more than 500 meters,is more challenging and difficult compared to drilling in land or shallow waters.And due to the difficulty of sampling seabed soil and the high cost,the understanding of the shallow strata is limited to 20 meters below the mud line,which further brings uncertainty to predict the bearing capacity of the strata and presents a challenge to the driving depth calculation of deep-water conduit.For the insufficient soil data,in this paper,the main mechanical parameters of shallow soil are obtained and the fitting relationship between porosity ratio,strength parameter of shallow soil and formation density are established through research and analysis of mechanical properties and formation characteristics of shallow formation.Based on the massive research and experiment,the law of lateral bearing capacity(lateral friction)variation with depth in cohesive and non-cohesive soil and the mathematical relationship between unit surface friction and soil parameters are studied.Also,according to the similarity theory,the relationship between the density of shallow soil,the porosity and the acoustic velocity is studied by indoor simulation experiment on the relationship between soil mechanics and acoustic velocity in shallow soil.The distribution rules of mechanical parameters of shallow soil and seismic P-wave velocity are established in order to better understand the mechanical properties of the shallow stratum with the existing seismic velocity data and provide a basis for calculating the formation bearing capacity and the reasonable driving depth of the marine conduit,which will be a reference for the drilling operation in the future.