###### Abstract
In addition, new techniques, such as biological grouting, have been increasingly applied to improve the strength of soil between piles [28]. In the case that a large diameter monopile cannot meet the loading and deformation requirements of the superstructure, the group pile is widely used due to its advantages of good integrity, small and uniform deformation and settlement, high bearing capacity, strong overturning resistance, and its ability to withstand large horizontal forces. However, the bearing discs of variable section group piles exhibit the problem of interacting with each other, resulting in a reduction in the group pile effect. To date, most relevant studies have focused on discontinuous solidified soil between piles. In the alluvial plain area with a large thickness obtained during the Quaternary period, due to the absence of a good holding layer within several tens of meters, there is a bottleneck in the lateral resistance of the pile that can be compensated with the soil around the weak pile. The magnitude of improving the bearing capacity by increasing the diameter and length of piles, improving the cross-sectional shape of piles, and reinforcing the soil between the piles is limited, which makes it difficult to satisfy the design requirements of high-rise and super high-rise buildings for high bearing capacity pile foundations. Accordingly, [PERSON] et al. [29] invented a group pile foundation called soil continuously solidified (SCS group pile foundation) between the pile systems and presented its construction method. This technique can be applied using rotary spraying methods such as MJS [30] to set up a continuous \"artificial holding layer\" in the dominant stratum, such as a sand layer underneath the group pile foundation. This system mainly consists of two or more foundation piles, bearing platforms, a continuously solidified part, soil between piles in the target layer, and soil between piles in the non-target layer. Both precast piles and bored piles can be used for the SCS group pile foundation, but the splicing of precast piles should be emphasized [31]. The upper end of the foundation pile is embedded in the bearing platform to a certain length and fixedly connected with the bearing platform, while the rest of the pile is buried in the soil layer. The continuously solidified part is set in the soil between the piles in the target layer. The SCS group pile foundation system is shown in Figure 1. [PERSON] et al. invented the SCS group pile foundation system and presented its construction method. This new method adopts the foundation treatment technology to continuously strengthen the target layer, which changes the current design idea of improving the bearing capacity of the pile group by improving the single pile. After reinforcement, the soil between the piles of the target layer forms a continuous and high-strength whole in the horizontal direction, which provides a good artificial holding layer for the group piles. Studies have shown that the continuous solidification of soil between piles to improve the pile-bearing capacity is a cost-effective method [32]; however, as a brand new pile type, its bearing mechanism urgently needs to be further clarified. We proposed to investigate the vertical compressive bearing performance of the continuously solidified group pile foundation with soil between piles in the sandy soil foundation on the basis of a model test combined with the theoretical analysis and observation of the dynamic change process of the foundation. This is important for the design and application of the SCS group pile foundation.