# Model Tests on Jacked Pile Penetration Characteristics Considering a Static Press-in Piling Machine
## 2 Model Test
### Testing Equipment  
The model test system, which considers the impact of the static press-in piling machine, primarily consists of the model test platform, the data acquisition system, the model pile, and the long leader models of the piling machine.  
The pile foundation model test platform comprises a self-designed loading system and a model box which is manufactured by Shanghai Zhubang Measurement and Control Technology Co., Ltd. in Shanghai, China. The loading system consists of a reaction frame, a power device, and three jacks. The reaction frame's overall structure comprises a base, two side reaction frames, and an intermediate reaction frame. The base measures 2.5 m in length, 1.9 m in width, and 0.2 m in height. The two side reaction frames are 2.5 m tall with a span of 1.9 m. The central reaction frame, standing at 2.8 m high, is constructed with a self-designed adjustable steel plate secured by four long anchor bolts. The jacks on both sides simulate the loading of the piling machine, while the middle jack is utilized for pile jacking. The model box is constructed from welded steel plates and measures 2 m \(\times\) 1.2 m \(\times\) 1.2 m (length \(\times\) width \(\times\) height, respectively), as illustrated in Figure 1.  
In accordance with the geometric similarity theory, the selection of the static press-in piling machine is scaled down in proportion to the actual project. The prefabricated long leader models of the piling machine measure 1 m \(\times\) 0.15 m \(\times\) 0.1 m (length \(\times\) width \(\times\) height, respectively), with a 0.6 cm distance between the long leaders. The combined load applied by each group of hydraulic jacks and the dead weight of the long leader model of the pile machine amounts to 0.68 t. Through the application of load and the grounding area of the long leader, the specific pressure of the long leader grounding is determined to be 45 kPa. Additionally, a 1 cm thick steel plate is placed under the concrete model to simulate the real contact between the static press-in piling machine and the ground. Figure 2 depicts the schematic diagram of the actual project and the model test of the jacked pile machine.  
The model pile is a solid cylindrical precast concrete pile. Given the boundary effect of pile jacking, the radial range of pile jacking in clay extends approximately 5 times the diameter of the pile away from the pile body. Based on the dimensions of the model box, the pile diameter is determined as D =100 mm and the length as L = 600 mm. The strain gauge grooves are reserved on the pile side, and the strain gauges are adhered to the groove of the low-strength solid model pile using the groove method. A total of 14 strain gauges were positioned on the model pile, with 7 on each side. Strain gauges with a base length of 4 mm were placed at the pile end and top, while strain gauges with a base length of 10 mm  
Figure 1: Pile foundation model test platform diagram. (**a**) Platform detail diagram. (**b**) Overall platform diagram.  
were positioned at other locations to enhance the precision of the measurement results. The surfaces of the strain gauges are coated with silica gel, and epoxy resin is used to seal the grooves before polishing the epoxy resin surface with sandpaper, in order to reproduce the pile-soil interaction as accurately as possible. Figure 3 depicts the layout diagram of the strain gauges. Following this, the groove is sealed with epoxy resin and polished to form a pile.  
The data acquisition system primarily utilizes the DH3816N static strain acquisition instrument which is manufactured by Donghua Testing Technology Co., Ltd. in Jiangsu, China and wireless earth pressure gauge manufactured by AVIC zhonghang Electronic Measuring Instruments Co., Ltd. in Shijiazhuang, China for collecting pertinent data.