Construction method for tunnel trunk penetrating through loess interface water-rich strata

Abstract

The invention relates to the technical field of tunnel construction, in particular to a construction method for a tunnel trunk penetrating through loess interface water-rich strata. The construction method comprises the following steps that (1) the geological condition of the strata where the tunnel truck passes is surveyed and analyzed, and the geological condition in front of a tunnel face is analyzed at the same time; (2) whether advance longhole curtain grouting is adopted or not is determined according to the stability situation of the tunnel face; (3) advance supporting is conducted, and excavation and supporting are conducted by means of a four-step and temporary cross bracing method; and (4) excavation, supporting and lining building are conducted on an inverted arch of a tunnel. According to the construction method for the tunnel trunk penetrating through the loess interface water-rich strata, the geologic structure of a loess interface is analyzed, and advance grouting and the four-step and temporary cross bracing method are adopted for the interface water-rich strata, so that mud bursting of the tunnel face in the water-rich interface strata is effectively suppressed, and conditions are created for excavation; and the four-step and temporary cross bracing method effectively prevents overlarge overall sinking and deformation damage of the tunnel trunk when the tunnel truck penetrates through the loess interface water-rich strata, and the construction method has very important guiding significance for design and construction of tunneling in loess-like strata.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, in particular to a construction method for a tunnel body passing through a water-rich stratum at a loess interface. Background technique [0002] In recent years, my country's infrastructure construction has developed rapidly. With the acceleration of domestic high-speed railway and western development, a large number of railways and roads have been built in Gansu, Shanxi, Shaanxi, Inner Mongolia, Qinghai and other provinces and cities in recent years. The soil-like deposits formed during the 19th century, so its properties are relatively loose and special. The typical loess is composed of yellow-gray or brown-yellow dust and fine silt particles. Or loess nodules, porous, with significant vertical joints, no bedding, hard when dry, easy to be soaked by running water, usually easy to peel off and suffer from erosion, and even collapse. Therefore, when carrying out various engineering...

AI Technical Summary

Problems solved by technology

[0003] The body of the loess tunnel passes through the weak stratum at the interface between the water-rich sand layer and the clayey loess, especially the water-saturated zone formed between the water-rich sandy loess layer and the impermeable cement rock stratum. Water, outbursts, collapse and instability of the tunnel face, overall subsidence and deformation lead to problems such as encroachment. The traditional construction method uses the three-step excavation method, but the three-step method has the problem of excessive settlement and deformation. The subsidence deformation can easily lead to safety and quality risks, and it is difficult to control the subsidence deformation by using the three-step method, and the construction efficiency is relatively low. The subsurface sand layer surges and collapses, which increases the construction cost and cannot effectively prevent the excessive overall subsidence, deformation and damage of the water-rich strata at the loess interface

Images