A Construction Method of Surface-Controlled Blasting Excavation for Ultra-large and Widening Sections of Tunnels

Abstract

The invention discloses a control blasting excavation construction method for a super-large widening section surface of a tunnel. The method is used in the technical field of tunnel construction. Themethod comprises the steps that 1, a common fracture surface is excavated at first; 2, after initial supporting and stable settlement are completed during the excavation of the common fracture surface, blasting excavation is conducted on a widening section, wherein the widening section is excavated by means of a step method, and a heightening part of a vault of the common fracture surface is excavated at first; 3, excavation is obliquely conducted in the direction from one end of the widening section to a side wall at a certain angle, forward pushing is conducted, after the widening section isexcavated to a designed contour line, an end wall at the other end is excavated by adopting a smooth surface blasting method, and initial supporting is conducted; reverse excavation is conducted at the same time, forward pushing is conducted by adopting the smooth surface blasting method according to an excavation method of common fracture surfaces, and then excavation and initial supporting of upper steps on the widening section are completed synchronously; 4, blasting excavation is conducted on lower steps at last. By means of the method, the excavation progress of the widening section is accelerated, risks at the construction period and idleness due to poor organization are avoided, the construction cost is greatly reduced, the construction procedures are simple, and the method can beused under the condition of short widening sections.

Description

technical field [0001] The invention is used in the technical field of tunnel construction, and in particular relates to a method for excavating by blasting and excavating with super-large section widening of the tunnel. Background technique [0002] With the large-scale construction of my country's highway transportation network and the large-scale construction of oil reserve bases in recent years, the design of tunnels has become more and more complex. In order to meet the needs of safety and pipeline equipment installation, the section of the widened section is compared with ordinary The section continues to expand. Especially for oil pipeline tunnels, the ordinary section design is relatively small, and in order to meet the space requirements of the expansion joint, the design of the widened section is more than twice as wide as the standard section, and the height is also increased by three to four meters, and the length of the widened section is relatively small , mult...

AI Technical Summary

Problems solved by technology

[0007] (1) The construction process is relatively complicated, and it is only suitable for use when the widening section is long

[0008] (2) When using this method, the construction of ordinary sections will be seriously affected, and cross operations cannot be realized, which will have a great impact on the construction period, and cause delays, which will significantly increase the construction cost

[0009] (3) It is difficult to effectively control over and under excavation in the widening section

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