Loess tunnel surrounding rock classification method

Abstract

The invention relates to a loess tunnel surrounding rock classification method. By means of the loess tunnel surrounding rock classification method, loess tunnel preliminary supporting and secondary lining can be performed in targeted mode, construction difficulty can be reduced, and construction safety and tunnel structure stability are ensured. The loess tunnel surrounding rock classification method adopts qualitative characteristic division and qualitative division combination method to perform comprehensive judgment; division is performed according to the indexes including loess formation age, plastic state, joint development degree, surrounding rock stability state after tunnel excavation and the like, and loess tunnel surrounding rock grades are subjected to division according to tunnel soil texture characteristics, underground water and tunnel deep embedding and other factors; loess surrounding rock grade indexes, an obtaining method and the correspondence relation between a loess (clay soil) surrounding rock humidity degree qualitative value and quantity are given.

Description

technical field [0001] The invention relates to a method for grading tunnel surrounding rock, in particular to A Surrounding Rock Classification Method for Loess Tunnels . Background technique [0002] In the background technology, loess is called "yellow soil" in ancient times, which originated from the color of the land and is a kind of Quaternary sediment. Loess is widely distributed in the world. The total area of ​​loess and loess-like soil distribution in the world is about 13 million square kilometers, accounting for 9.3% of the total land area. my country has the largest distribution area of ​​loess in the world nation , with a distribution area of ​​640,000 square kilometers, accounting for country 6.3% of the soil area. In the middle reaches of the Yellow River, from the Helan Mountains in the west to the Taihang Mountains in the east, from the Great Wall in the north to the Qinling Mountains in the south, almost all of them are covered by loess, covering an ...

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Problems solved by technology

my country has built a large number of single- and double-lane railways and two-lane road tunnels in the loess area. Although it has accumulated rich experience in engineering practice and achieved a considerable number of achievements in loess tunnel engineering, there is no corresponding classification for the surrounding rock classification of loess tunnels. However, the parameter indexes of rock surrounding rocks are almost completely inapplicable to loess surrounding rocks, and the existing relevant codes cannot provide suggested values ​​for the main calculation physical and mechanical parameters of loess surrounding rocks.

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