# The Influence of Metro Tunnel Construction Parameters on the Settlement of Surrounding Buildings
## 1 Introduction  
Today in tunnel construction, the tunnel boring machine (TBM) is used, equipped with a device for maintaining the ground at the face under various soil conditions to ensure the safety of the construction process, known as face-support pressure. At the same time, even with the use of advanced methods, the construction of tunnels can affect previously built buildings and infrastructure facilities [1; 2]; however, the efficiency and reliability of the metro system greatly influence the transportation, economic, environmental, and social aspects of cities [3]. Therefore, determining additional displacements resulting from the construction of the facility is an important task. Determining the extent of surface subsidence is intrinsically a relevant issue; for example, land movement can cause damage to property and resources due to groundwater [4]. Currently, at the design stage, engineers are addressing two parallel tasks: (1) assessing the impact of the new construction on the surrounding buildings, assuming that face stability is ensured and there is no emergency situation, and (2) determining the face-support pressure required to maintain face stability and minimize ground surface settlement. The first task is the assessment of additional displacements and is carried out in software packages based on the finite element methods with an optimized soil coefficient parameter [5]. The second task of determining the face-support pressure is carried out at the design stage, taking into account the engineering and geological conditions and the depth along the entire tunnel route. The modern method for determining face-support pressure is considered a preliminary forecast due to the high degree of uncertainty in engineering and geological conditions and requires adjustment of the pressure value during the tunnel construction. Furthermore, during the tunnel construction, surveyors and the tunneling crew again solve different tasks in parallel: surveyors monitor the deformations of the surrounding buildings, and the construction team monitors the technological indicators of the tunneling process. Thus, tools are required to coordinate these two tunnel construction processes. The most renowned empirical study in the field of determining surface settlement during tunneling operations was conducted by the scientist [PERSON] [6], who adapted the Gaussian normal distribution curve to describe the settling of the Earth's surface using data obtained during the construction of the London Underground. [PERSON] and [PERSON] [7] analytically described surface settlement in clay and sandy soils. Later, [PERSON] and [PERSON] [8] considered surface settlement taking into account tunnel ovalization, which is caused by the compression of the soil mass in which construction is carried out. Face-support pressure also influences additional movements of buildings located in the area affected by tunnel construction [9]. Therefore, time is dedicated separately to inventing methodologies capable of selecting the necessary face-support pressure to maintain face stability. There is an analytical solution [10] that considers multi-layer soil, the support pressure gradient, and the water table level, distinguishing this work from many others. Settlements in the longitudinal section of the planned tunnel are also studied, and it has been established that, in some cases, upward vertical movements (blow-out) have been recorded [2]. Numerical methods for determining the impact of tunnel construction on the surrounding structures are also currently popular, where the influence exerted on settlement by factors such as the relative depth of tunnel placement [11], soil models [12, 13], dimensions of the structure, and the load that the structure exerts on the foundation [13] are studied. Other authors have also used numerical analysis and monitoring data to determine the patterns that influence surface deformations [14].