## 1 Introduction  
When reinforcing soft soil foundations using tubular piles, their penetration and relevant construction effects could influence the resistance against pile settlement and the failure mode and bearing capacity of the piles. Therefore, these effects have a significant influence on the bearing capacity of the composite foundation [1]. Currently, the dial indicator contact measuring method, static load testers, tile marking measuring method, inclinometer measuring method, and accelerometer measuring method are commonly used to monitor the penetration of tubular piles. For example, [PERSON] et al. analysed the pile settlement laws of PHC tubular piles by determining the blow counts of settled piles, further optimising the penetration design of tubular piles through the incorporation of geological exploration data [2]. Further, [PERSON] et al. simulated real piles by using square steel bars and marked scales on the bars to measure the penetration depths of the piles [3]. Studies on the construction effect of large-diameter tubular piles mainly focus on the evolution mechanism and influencing factors of the construction effect and the bearing capacity of pile foundations based on the construction effect. Concerning the evolution mechanism of the construction effect of tubular piles, [PERSON] et al. monitored the hyperstatic pore pressure and soil mass displacement through field tests, analysed the squeezing effect of high-rise platform tubular piles in soft soil regions, and determined the dissipation laws of hyperstatic pore water pressure and variation characteristics of soil mass displacement caused by pile settlement [4]. [PERSON] et al. carried out statistical analyses on soil plug data during the penetration of 44 PHC piles (60-65 cm) from three sites and five types of typical soft soil foundations in Shanghai. They concluded that the IFR and soil plug ratio (PLR) had a linear relationship. Moreover, the empirical formula was fitted [5]. [PERSON] et al. analysed the settlement laws of PHC tubular piles by observing the blow counts, finding that PHC tubular piles had a very strong squeezing effect on surrounding soil masses [6]. [PERSON] et al. studied the pile-soil interaction of open-ended and closed-ended piles through finite element analysis and determined the stress mechanism of soil plug soils under different vertical loads [7]. [PERSON] et al. proposed a calculation formula for the soil plug height based on the Terzaghi theory of ultimate bearing capacity [8]. [PERSON] et al. studied the influences of tubular pile diameters and other factors on the evolution laws of soil plugs using discrete element numerical simulation software [9]. Concerning the influencing factors of construction effects, [PERSON] et al. simulated the piling process of steel tubular piles in sandy soils and explored the influences of the pile diameter, piling energy, and elasticity modulus of soils and bearing strata on the plugging effect. The researchers believed that the piling energy was the primary influencing factor of the plugging effect, followed by the pile diameter, penetration depth into bearing strata, and elasticity modulus of the soil mass [10]. [PERSON] et al. simulated the settlement process of open-ended tubular piles of different models based on the particle flow program PFC2D. They then determined the macro-mechanical response mechanism during settlement by analysing the microscopic changes in the soil mass. The results demonstrated that the diameter of the tubular piles influences the plugging effect significantly. With an increase in this diameter, the plugging effect decreased quickly [11]. Further, [PERSON] et al. carried out field penetration tests on 17 groups of open-ended and closed-ended model piles into clays and found that the radius-thickness ratio and diameter of the tubular piles influenced the soil plug height greatly. Moreover, they found a linear relationship between the IFR and soil plug ratio (PLR).