Generation and Characteristics of Construction Noise in Rail Transit Engineering Enclosure Structures

Rail transit is an important part of the urban transportation system, while the noise generated during construction seriously affects the engineering personnel and surrounding residents. To investigate the noise emissions and characteristics during the construction of the enclosure structures in the rail transit engineering project, an empirical study is conducted through on-site surveys, semi-structured interviews, and experimental monitoring. The results indicate that during enclosure structure construction, there are nine key noise-emitting machines and four key noise-generating construction processes. Among them, the equivalent average sound levels of six machines, including pneumatic hammers, pneumatic drills, concrete pump trucks, construction drills, rotary drilling rigs, and grooving machines, exceed 80 dB(A). The energy contribution rate curves of machine spectra peak at 63 Hz, 500 Hz, 1000 Hz, and 4000 Hz, which have certain effects on construction personnel and nearby residents. Meanwhile, guide wall construction, groove construction, reinforcement cage fabrication and hoisting, and concrete pouring are identified as key noise-generating construction processes. This empirical investigation helps to establish a theoretical basis for noise control during the construction of enclosure structures in urban rail transit engineering projects, and the results provide valuable references for the formulation of auxiliary noise reduction measures.