## 1 Introduction  
The anti-sliding capacity of the foundation base [1, 2] is the key to the control and design of the horizontal bearing capacity of a series of large-scale gravity foundations, such as the ground connecting wall anchorage foundation and caisson foundation of suspension bridge, offshore wind power gravity foundation and floating platform mooring gravity anchor block. [PERSON] et al. [3] showed that the interface friction between foundation and soil is the key to resist horizontal load. [PERSON] et al. [4] divided the process of relative slip between soil mass and anchorage into three stages, and explained the formation process and mechanism between each stage. In general, the anti-sliding bearing capacity between the base and the foundation soil is mainly reflected by the base friction, which is obtained by multiplying the vertical pressure of the base by the base friction coefficient [5; 6; 7]. The existing research and engineering application have mainly focused on the constant vertical pressure, but the research on the friction characteristics under the vertical pressure changes caused by construction operation and other factors is not sufficient, which adds uncertainty to the accurate control of the whole process load. Meanwhile, during the construction of the increasingly large-scale foundation, it is necessary to strengthen the foundation with insufficient original bearing capacity. For example, the foundation base of the anchor foundation of the world's first-span (2300 m) Zhang Jinggao Yangtze River Bridge under construction is reinforced with cement soil. [PERSON] et al. [8; 9; 10] studied the influence of total water cement ratio on unconfined compression behavior, consolidation characteristics, triaxial compression characteristics and microstructure of soil cement, and found that soil cement with cement as the curing agent has the advantages of rapid construction, significant improvement of foundation bearing capacity and good economic benefits. A coastal wind power plant is also reinforced with cement mixing pile for shallow deep soft soil [11]. The research on the interface shear properties of concrete cement soil and concrete in-situ foundation soil under dynamic normal pressure is also relatively scarce, which increases the difficulty of reasonable evaluation of interface shear properties. Further, for the super-large diameter pile foundation, with the increase of pile diameter, the size effect of vertical side friction is gradually increased, and the relevant experimental research is currently scarce. Therefore, it is of great engineering significance to study the interfacial shear characteristics between different structural materials and different soils under dynamic normal pressure. The interface friction coefficient between the soil and structure is mainly measured by the interface shear test. [PERSON] et al. [12] verified through FLAC3D that the shear parameters of the wall rock filling interface have an important influence on the vertical stress distribution of the stope filling body. [PERSON] and [PERSON] [13; 14; 15] used direct shear equipment to test and study the shear properties of sulfate, curing temperature, curing stress, drainage conditions and filling rate on the wall rock filling body interface through a series of auxiliary tests to explain the macro mechanical phenomenon. However, the previous studies in this field have been focused on the constant normal pressure, ignoring the change of normal stress in the shear process. On the other hand, the traditional interface shear test cannot pressurize the samples in the shear process [16; 17; 18], which also leads to the lack of interface shear test research between different structural materials and different soils under variable normal stress. For this reason, [PERSON] et al. [19] carried out a series of shear tests on the sand concrete interface and obtained the mechanical properties of the interface under the condition of continuous graded compression of normal stress. [PERSON] et al.