As the key index of geotechnical engineering investigation, soft soil parameters are the premise and basis for studying soft soil characteristics and solving soft soil engineering problems. Taking the deep soft soil in Nansha port area of Guangzhou as the research object, 371 groups of indoor geotechnical tests and 147 groups of field in-situ test data were collected, and the spatial characteristics of soft soil parameters are studied by mathematical statistics and random field theory. The results show that: Soft soil shows "four high and one low", to be specific, high water content, high liquid limit, large void ratio, high compressibility and low shear strength, it has strong regional and spatial heterogeneity, and the space-time effect is significant; The empirical formula between soft soil parameters are established, it is showed that the physical indexes of soft soil have better stability, smaller coefficient of variation and stronger correlation than the mechanical indexes; The water content, void ratio, compression coefficient, liquid limit and liquid-plastic limit index decrease with the increase of soft soil depth, while natural density, compression modulus, strength index and static cone penetration index increase slowly, the shear strength of vane first decreases and then increases; The autocorrelation distance has no obvious correlation with the increase of exploratory hole depth, the cone tip resistance index can better reflect the spatial variation characteristics of soil layer and the reproducibility of test results, and realize the transformation of soft soil parameters from "point" characteristics to "spatial" characteristics; The recommended value of soft soil judgment standard in this area is put forward, which provides a reference for the survey and design, soft foundation treatment and construction of silt soft soil in similar areas.

In order to further study the propagation characteristics of surge wave induced by underwater blasting loads, the multi-physical field coupling simulation method powered by the dynamic analysis software COMSOL was adopted to establish a transient solution model based on the second water source project-diversion project of Guilin City. The isosurface, peak stress and vibration velocity of surge wave under explosion load were studied and evaluated based on field monitoring results. The results show that the surge wave produced by underwater blasting essentially propagates around the center of the blast center, and the surge isosurface evolves from regular round to irregular ellipsoid with time. The surge waves decay rapidly during propagation, and with the increase of water medium velocity threshold, the influence range of surge wave action region is small. In addition, the stress of the surge wave has superposition effect under the condition of delayed blasting, and thus there are multiple peaks. When the distance to blast center increases from 28 m to 108 m, the attenuation rate of the peak vibration velocity of the surge wave reaches 96.3%, which has little effect on the structure. Meanwhile, the time of the peak velocity of the surge wave increases gradually with the increase of the distance to blast center.