JPS61159100A - Smooth section excavation method in tunnel execution of collapsible base rock - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The necessity of smooth plasting has long been pointed out in tunnel construction, and the importance of smooth cross-section excavation has been recognized, especially in the recent Natome method, and various methods have been proposed. .

All of them lack a decisive factor and have continued to this day. The present invention provides a safe and inexpensive smooth cross-section excavation method that requires little extra digging, especially in tunnel construction through rock that is highly prone to collapse. The present invention will be explained in detail below with reference to the drawings.

In Figure 1, a plurality of core blasts are drilled in the center of the tunnel design excavation section 1.

Between the blast cross section 3 and the designed excavation cross section 1, a rock mass with the required thickness remaining after excavation of the outer periphery is left. After that, holes of the required spacing and depth are drilled in the rock having the remaining thickness of the excavation.2 The holes are placed in a large capsule 5 filled with an oxidizing agent 4 such as manganese peroxide that generates oxygen through thermal decomposition as shown in FIG. As shown in Fig. 3, a heat reaction limiting explosion pressure capsule 100 containing a small capsule 7 filled with a fuel 6 such as kerosene was inserted into the hole end 10 of the reader tag 9, and then a capsule containing quicklime as the main component Static expanded crushed material (
Product name: S-Mite, etc.) Sura'J-
11, or a capsule made of a static expansion crushing material is hydrated and filled, and a reaction accelerating capsule 12 made of quicklime or quicklime and cement is hydrated and filled in the mouth of the reader tag 9, and the hydration reaction of the reaction accelerating capsule is carried out. The exothermic hydration reaction of the slurry in the vicinity of the reaction promoting capsule is promoted by heat, and the exothermic hydration reaction of the slurry proceeds sequentially toward the hole end, and the exothermic reaction of the slurry at the hole end limits the thermal reaction limiting explosion pressure. The oxidizing agent 4 in the capsule 100 is thermally decomposed to form an oxygen reservoir at the end of the hole 10, and the fuel 6 in the small turnip is vaporized and spontaneously ignited to generate explosive pressure and hydration expansion of the statically expanding and crushed material. This method uses pressure to statically crush the rock mass remaining in the thickness remaining after excavation on the outer periphery, and performs smooth cross-sectional excavation with little over-excavation.

The blending ratio of oxidizer and fuel in thermal reaction-limited detonation capsules is determined by a chemical reaction equation, and the dosage is rock-solid.

It is determined by the blast pressure required depending on the condition of the holes and other factors.

Recently, the application of water jet to tunnel excavation has become popular.2 As shown in Fig. 4, a slit 14 is made in the outermost hole n of tunnel excavation by using a water jet in the direction of the adjacent hole.

If crushing is carried out in the same manner as described above, excavation can be carried out more effectively.

Furthermore, if the earth cover is shallow or if core blasting is not possible due to the proximity of private houses, a core hole 15 is drilled in the center of the tunnel excavation as shown in Figure 5, and the area around the core hole 15 is Drill V-cut holes 16 to 18 etc. in the core hole 1.
It becomes possible to statically excavate a tunnel by constructing the holes 16 on the outer periphery in order from the hole 16 close to the hole 5 and proceeding with crushing in the above-described manner.

As is clear from the above description, the present invention uses a static expansion crushing material and a thermal reaction limited explosion capsule to statically, safely, and inexpensively construct tunnels that are particularly susceptible to collapse, and to achieve smooth construction with less excess trench 9. This makes it possible to excavate a wide cross section.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the tunnel excavation method according to the present invention. Figure 2 is a schematic diagram of a thermal reaction limited explosion capsule 1 Figure 3 is a diagram of the construction procedure according to the present invention 2 Figure 4 is a schematic diagram of a case where a slit is provided in the outermost hole of tunnel excavation by water jet, and Figure 5 is a diagram of core removal A schematic diagram showing the construction procedure without blasting. ■・・・Design excavation cross section Medical... Core blasting hole 3... Blast cross section 4...
・Oxidizer 5... Large capsule 6... Song fuel 7
...Small capsule

Claims (1)

[Claims] In the construction of tunnels in collapsible rock, the central part is blast-excavated in a core-like manner, leaving the required thickness of the outer circumferential excavation remaining for the designed excavation cross section, and then holes are drilled at the required intervals in the outer circumferential rock remaining after excavation. A thermal reaction limiting explosion capsule is inserted into the bottom of the hole, which consists of a large capsule filled with an oxidizing agent such as manganese peroxide that generates oxygen through thermal decomposition, and a small capsule filled with fuel such as kerosene. Then, a slurry made by kneading a static expansion crushing material mainly composed of quicklime with water is filled, and a reaction accelerating capsule made of quicklime or quicklime and cement is moistened and filled at the mouth of the hole. The hydration reaction heat of the reaction accelerating capsule promotes the hydration exothermic reaction of the slurry in the vicinity of the reaction accelerating capsule, and the hydration exothermic reaction of the slurry proceeds sequentially toward the hole end, thereby causing the exothermic reaction of the slurry at the hole end. The oxidizing agent in the thermal reaction limited explosion capsule is thermally decomposed to form an oxygen reservoir at the bottom of the hole, and the fuel in the small capsule is vaporized and spontaneously ignited, resulting in the explosion pressure and water in the static expansion and crushing material. A smooth cross-section excavation method for tunnel construction in collapsible rock, which is characterized by statically crushing the rock mass with the thickness remaining after outer circumferential excavation using combined expansion pressure to perform smooth cross-section excavation.