The evaluation of artificial filling in loess areas by in-situ tests based on statistical analysis

To control the deformation disaster and explore the effective in-situ evaluation method of filling in the Loess Plateau of China, the laboratory tests and cone penetration test (CPT), dynamic penetration test (DPT), standard penetration test (SPT) were carried out for a case of filling with large area. The research was performed based on data distribution, non-uniformity evaluation, correlation and sensitivity analysis. The results are as follows: (1) the filling filled by layered compaction still has non-uniformity. The distribution of CPT tip resistance is consistent with collapsibility coefficient and obeys logarithmic normal distribution. The distribution of CPT side friction and SPT hammer number are consistent with moisture content, void ratio and dry density and obey normal distribution. The distribution of DPT hammer number does not correspond to any soil properties index. The CPT also has the advantages to reflect layered compaction characteristics along filling depth and distinguish the boundary between filling and undisturbed soil. (2) Three test methods can all reflect the non-uniformity of soil properties in depth direction. However, for the horizontal direction, the CPT results can best reflect non-uniformity of actual collapse deformation, followed by SPT and DPT is the worst. (3) For the testing of filling compaction state, CPT tip resistance and SPT have good mathematical correlation, and the sensitivity of CPT tip resistance is significantly higher than other methods. For the testing of filling collapse deformation capacity, the CPT tip resistance, DPT and SPT all have good correlation and sensitivity. So CPT tip resistance has the best cooperation between correlation and sensitivity. (4) The CPT (especially tip resistance part) can be effectively applied to the properties evaluation of silty loess filling. The tip resistance to void ratio and collapsibility coefficient follow the exponential function and logarithmic function respectively.