The support in the bottom-hole zone of the trunk is a system of rings made of monolithic concrete having a different hardening period, which increases from the face up the trunk and is determined by the duration of the tunneling cycle. The strength and deformation parameters of the concrete support depend on the age of the concrete. Thus, to determine the strength of concrete in the early stages of concrete hardening, various empirical dependencies are used that link the strength of concrete at the design age with the strength at the required age. Based on a series of calculations performed by the finite element method, it was found that the change in the penetration rate does not significantly affect the relationship between stresses and deformations when static equilibrium is reached in the ""support – array"" system, which occurs at a high penetration rate at a greater distance from the bottom of the trunk. At the same time, intensive loading of the support at an early age can disrupt the process of natural hardening of concrete, lead to a violation of its structure, the development of fracturing, which will entail a decrease in the bearing capacity and water resistance of the support, a decrease in its durability.
Keywords: shaft, sinking, support, concrete, stress, deformation, strength, bearing capacity
There was a need for geotechnical monitoring during construction of underground facilities. The organization of monitoring control tensile forces in the concrete anchors. Comparison of experimental and calculated data, which revealed that the deviation does not exceed 19%. When using anchor embedment length limited in a large range of conditions in a rod anchor having critical internal forces. To increase the efficiency of anchors in their construction can be used in flexible elements of the anchor bolt assembly.
Keywords: underground construction, monitoring, anchor well, tensile forces, the bearing capacity, the compliance node
In the article numerical simulation of the interface zone of a tunnel with a vertical barrel by the finite element method is considered. The numerical spatial model is a fragment of a rock mass with a size of 80 to 90 meters, in which the tunnel is connected by a span of 6.0 m, adjacent to the vertical trunk. The mating and trunk in the area under consideration are fixed with reinforced concrete lining 500 mm thick. A universal spatial isoparametric eight-node finite element is used to break up the model. The dimensions of the finite elements on the outer regions of the model were 2.5 - 5.0 m, on the inner - 0.25 - 0.5 m. Thus, the principle of combining dense and rarefied grids was used to reduce the amount of information describing the numerical model. The problem was solved in an elastoplastic formulation by a stepwise iteration method. As a result of calculations, all the components of the volumetric stress tensor in the finite elements of the lining and the rock mass, movement and deformation in the nodes of the finite elements were determined. With the help of the developed numerical models, a series of calculations was performed, an array of data was obtained on the stress-strain state of the lining in the zone of coupling effect, quantitative and qualitative analysis was performed. It is established that in characteristic zones of the influence of conjugations, a significant increase in the intensity of equivalent stresses is observed, which leads to a reduction in the load-bearing capacity of the lining by 2 times or more in comparison with extended sections of underground structures. To increase the efficiency of maintaining interfaces during tunnel operation, it is necessary to justify the control actions taking into account the dynamics of changes in the stress-strain state of the lining in space and time.
Keywords: tunnel, shaft, linking, stress-strain state of the rock mass, the concrete lining
There was a need for geotechnical monitoring during construction of underground facilities. The organization of monitoring control tensile forces in the concrete anchors. Comparison of experimental and calculated data, which revealed that the deviation does not exceed 19%. When using anchor embedment length limited in a large range of conditions in a rod anchor having critical internal forces. To increase the efficiency of anchors in their construction can be used in flexible elements of the anchor bolt assembly.
Keywords: underground construction, monitoring, anchor well, tensile forces, the bearing capacity, the compliance node
The article presents the main results of theoretical and experimental research in the field of non-destructive testing and forecasting of geomechanical condition of the arched part of the transport tunnels. It has been shown that this goal can be to apply a method of acoustic resonance inspection. Methodology Research was registering the resonant response of the layered rock mass to impact mechanical excitation of an acoustic signal. Initiation and receive elastic vibrations produced in the lower layer of the breed. These technical and economic parameters allow to recommend Geophysical prediction described underground geophysical methods for wide industrial use during transport tunnels
Keywords: geomechanical state geological environment, the array, evaluation, arched part, the transport tunnel spectrum, acoustic resonance inspection, prognostication, control, forecast, weakened mechanical contact