Calculation-theoretical justification of the compensation grouting parameters for the metropolitan railway protection from sedimentary deformations

An increase in the volume and scale of underground space development, including the construction of metropolitan railway facilities in large cities, is accompanied by a significant impact on the surrounding urban development, which requires the development and implementation of a set of special measures to protect buildings and structures from excess deformations. At the same time, numerous above-ground and underground structures are involved in the area of influence of the construction, including existing metropolitan railway facilities, as well as residential buildings and above-ground transport facilities. Сurrently, one of the most effective methods that provide reliable facilities protection from sedimentary deformations is the compensation grouting method. The article outlines the theoretical foundations for the use of compensation grouting technology to protect buildings and structures from excess sedimentary deformations during the construction of transport infrastructure facilities in dense urban areas. A mathematical model has been developed that corresponds to the actual geometry of the computational area of the metropolitan railway lobby with a soil base, the actual physical and mechanical characteristics of the materials of its structures, and the soil mass. The article presents the computer modeling results, with its help determined volumes, pressure, sequence, and injection sites. Based on calculated data, the duration of the special solution compensatory injection was determined to maintain a stable position of the foundations of the metropolitan railway escalator tunnels by forming the calculated stress-strain state of the soil mass at the ground slab base of the structure to provide a given preventive lift, the dependences of the lift deformations on pressure and the grouting volumes of special mixtures were established. Based on the obtained data, a procedure was developed for the production of work to maintain the planned-altitude position of metropolitan railway facilities at all construction stages and operation of the multifunctional complex.