Abstract: In order to study the suitability of different types of piles for diatomite foundations, deformation characteristics and protective measures of diatomite slope under rainfall, deformation characteristics of pile-raft composite foundation and subgrade bed dynamic response in diatomite, field loading test on single pile, rainfall on diatomite slope, bearing capacity of composite foundation and in-situ dynamic excitation tests were conducted on the Hangzhou-Shaoxing-Taizhou high speed railway. The result shows that CFG pile, plain concrete pile, reinforced concrete pile can be applied to diatomite foundation, whereas the screw pile is inapplicable due to compaction effect and high pressure rotary jet pile due to poor quality effect. The natural diatomite slope has connecting cracks that form network within the slope under drying-wetting cycles, resulting in insufficient shallow stability. The arch-shaped skeleton revetment has a better protective effect on the diatomite slope, while drilling during the construction of anchor frame beam will lead to the softening of diatomite, which is not suitable for the protection of diatomite slope. The CFG and plain concrete pile-raft composite foundation can satisfy the requirement for deformation control, and the structural integrity of concrete pile raft is better between the two types of piles. The capillary drainage layer has a good drainage effect, which ensures that the water can be discharged in time to avoid the adverse impact on the diatomite foundation.

Key words: Hangzhou-Shaoxing-Taizhou high speed railway, diatomite subgrade, field test, composite foundation, slope protection, waterproof and drainage subgrade bed