The variation in characteristic values of stress waves before and after passing through a material serves as a critical basis for evaluating its wave attenuation capacity. This can be characterized by the ratio of transmitted wave amplitude to the initial incident wave amplitude (i.e.

transmission coefficient) in SHPB tests. However

due to the close correlation between the transmission coefficient and waveform parameters

it remains challenging to establish a quantitative characterization method for the transmission coefficient. Therefore

this study focuses on porous

irregular

and fragile calcareous sand as the research object. By combining physical experiments with numerical simulations

we investigate the influence of pulse width

platform duration

rising edge rate

falling edge rate

peak stress

and the central axis of symmetry on the transmission coefficient of calcareous sand. It is found that the transmission coefficient responds significantly to the coupling effects of the pulse width and the central axis of symmetry of the stress wave

the coupling effects of the platform section duration and the rising and falling edge rates

the coupling effects of the pulse width and the peak stress

as well as the coupling effects of the falling edge rate and the pulse width. Conversely

the response to the coupled effects of peak stress

rising edge rate

and falling edge rate is not pronounced. Owing to the difficulty in completely decoupling these waveform parameters

a prediction method is proposed for the transmission coefficient based on the gradient boosting algorithm

which effectively addresses multi-factor coupling issues. When the number of training samples reaches 91

the prediction accuracy exceeds 96%

which can effectively establish the mapping relationship between waveform parameters and transmission coefficients

providing a reference basis for the load design and calculation of protective engineering structures.