JPH0718650A - Geological survey method for working face front natural ground in blast excavation method - Google Patents

Abstract

PURPOSE:To provide the geological survey method capable of obtaining an economical and high-certainty survey result, allowing a quick survey, shortening the stop period of a tunnel excavation to the utmost, shortening the construction period, and reducing the survey cost. CONSTITUTION:A bit 4 at the tip section of the rod R of a rock drill 3 is replaced with a core bit 10 capable of collecting a sample during or after the excavation of an explosive loading hole 2 by the rock drill 3 into the working face front natural ground 1. The core bit 10 is inserted into the hole 2, the rod R of the rock drill 3 is driven to rotate the core bit 10, and a rock core is collected from the working face front natural ground 1 and surveyed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a geological survey method for a ground in front of a cutting face when excavating a tunnel or the like by a blast excavation method.

[0002]

2. Description of the Related Art As a construction method for excavating a tunnel in a hard rock mass, there is a blast excavation construction method using explosives. This blast excavation method is a method in which the ground in front of the face of the tunnel or the ground to be expanded is drilled, explosives such as dynamite are loaded into the drilled hole, and the ground is broken down to explode the ground. .

By the way, in excavating such a tunnel, if the geology of the ground ahead of the tunnel face can be grasped before excavating the ground, a more appropriate construction method can be selected and the tunnel can be constructed safely. Therefore, various methods have been considered from the past, but the current situation is that there is no reliable method at low cost, and the most reliable method was to investigate the geology in front by continuous boring from the cutting face. .

[0004]

However, in such a method based on the front face drilling for cutting face, it is possible to grasp the rock type / rock quality and its mechanical properties by certainly collecting the rock core in front of the face face. Although it is possible to obtain a reliable survey result because it is possible, new equipment cost and labor cost for survey boring will be added, and the cost will be high, and tunnel excavation will be completely stopped after each survey boring Since it was necessary, there was a problem that the process was delayed.

As a method for investigating without collecting a rock core, for example, a bit is drilled with a hydraulic jumbo drifter,
At this time, there is also a method of grasping the hardness of the rock mass by the drilling speed and torque, and a color of the rock mass by the drilling slime, but it takes time and cost to record for grasping it and it is accurate. However, there is a problem that it is difficult to understand the rock type, rock quality, and mechanical properties, and it is difficult to understand the strength and properties of discontinuous surface.

The present invention has been made in consideration of the above points, and it is possible to obtain an economical and highly reliable survey result, and to enable a prompt survey, thereby making the tunnel excavation suspension period. The purpose of the present invention is to provide a geological survey method for the ground in front of the cut face in the blast excavation method, which shortens the construction period as much as possible, thereby shortening the construction period and reducing the survey cost.

[0007]

The invention according to claim 1 is
During or after excavation of the explosive loading hole in the rock face in front of the rock face with the rock drill, the bit at the rod tip of the rock drill is replaced with a core bit capable of sampling, and then this core bit is It is characterized in that it is inserted into a drilling hole, the core bid is rotated by driving a rod of a rock drilling machine, and a rock core is collected from the rock mass in front of the cutting face and investigated.

[0008]

According to the method of geological survey of the ground in front of the tunnel face according to the first aspect, the excavator for excavator loading is excavated, or in the middle of the excavation, only by exchanging the rock drill bit with the core bit. It will be possible to collect rock cores as survey samples. In addition, since the rock drilling machine used for drilling holes is used as it is during blast drilling, no special equipment is required, and therefore the cost and time required for the survey are almost zero, and the economy is low. The results of the survey can be obtained accurately, quickly and with high certainty.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the accompanying FIGS. As shown in FIG. 1, the method of geological investigation of the rock front rock mass in the blast excavation method according to the present invention is as shown in FIG. Alternatively, after excavation, the bit 4 at the tip of the rod R of the rock drill 3 is replaced with a core bit 10 capable of sampling, and then the core bit 10 is inserted into the drill hole 2 to make a rod of the rock drill 3. This is a method in which the core bit 10 is rotated by driving the R to collect a rock core from the ground 1 in front of the cutting face and to investigate this.

Next, these details will be described.
In the blast excavation method, first, a plurality of drill holes 2 are drilled from a face of a tunnel to a ground 1 in front of the face by a rock drilling machine 3 such as a hydraulic jumbo drifter, and then the dynamite is formed in the bore 2. By repeating the process of loading explosives such as etc., exploding this and cutting down the ground,
The excavation of the natural ground 1 is advanced, but in the geological survey method according to the present invention, the excavation process of the drilling hole 2 is effectively used without further survey boring for the geological survey. The rock drilling machine 3 used in 1) is used in place of the boring machine for geological survey.

That is, the rod R of the conventional rock drilling machine 3 for excavating the drilling hole 2 has a bit (button bit, for example, as shown in FIG. 2) at the tip thereof so that the drilling of the drilling hole can be performed efficiently. Etc.) 4 is provided, and the drilling hole 2 is excavated while crushing the rocky ground by flea rotation and impact to form slime. Therefore, even if the drilling hole 2 is excavated by such a rock drilling machine 3, the rock core cannot be sampled as in the case of the survey boring.

Therefore, as shown in FIG. 3, a core bit 10 comprising a bit 11 at the tip, a core tube 12 from which a core is sampled, and a joint sleeve 13 connected to a rod.
Prepare the core bit 10 with the rod R of the rock drill 3
The method used in combination with is used.

Regarding the time of use of the core bit 10, after the drilling hole 2 for loading explosives is drilled by the rock drill 3,
Alternatively, as shown by the broken line in FIG. 1, just before the drilling of the drilling hole 2 is completed, the bit 4 of the rock drill 3 is removed from the rod R, and the core bit 10 is attached to the tip of the rod R instead, and the drilling is performed. The rock core at the back of the drilled hole 2 is sampled by inserting it into the hole 2 and rotating the rod R and feeding water. Here, in the core bit 10, as shown in FIG. 4, a core tube 12 is screwed to a cylindrical bit 11 having a cutting tip T at its tip, and a joint sleeve 13 for connecting a rod R to the core tube 12. Has been screwed together.

In this way, several rock cores at required locations are sampled and investigated, and the geological condition of the ground in front of the face of the tunnel is grasped. In order to understand the geological condition, visual confirmation of spring and core conditions and a simple mechanical test at the current position are used to understand rock type, rock quality, crack characteristics, hardness and strength. If necessary, collect rock samples from the top of the crown and the sides of the tunnel.

When the geological survey method is carried out by such a method, after excavating the drilling hole 2 for loading explosives or in the middle thereof, the bit 20 of the rock drill 3 is simply replaced with the core bit 10. It is now possible to collect rock cores as survey samples, which allows visual confirmation of rock species, rock quality, and discontinuity properties several meters ahead, and simple mechanical tests to understand mechanical properties. Since it can be done, feedback to the construction (excavation method, examination of the validity of Shiho pattern, examination of whether it is necessary to use auxiliary method together) can be performed.
Moreover, by collecting rock cores in front of the cutting face, generality can be given to the evaluation of the rock mass in front of the cutting face.

Further, since the rock drilling machine 3 such as the hydraulic jumbo drifter used for excavating the drilling hole 2 is used as it is during the blasting and drilling hole, no special equipment is required, and therefore, for the purpose of investigation. The geological survey can be carried out economically and quickly with almost no cost and time, and as accurately as the survey boring. And
If the information is insufficient, it is possible to grasp the geology in front of the face in more detail by making several points on the face.
In addition, rock samples from the top of the crown and the sides of the tunnel can be collected as needed, so that geological information other than the rock to be excavated can be grasped.

[0017]

As described above, in the geological survey method for the ground in front of the cutting face in the blast excavation method according to the present invention, a rock drill is used to excavate a hole for loading explosives in the ground in front of the cutting face. During or after excavation, replace the bit at the rod tip of the rock drill with a core bit that can be sampled, then insert this core bit into the hole and rotate the core bit by driving the rock drill rod. As a method of collecting rock cores from the front of the cutting face and investigating them, it is possible to obtain economical and highly reliable survey results, and to enable swift surveys to enable tunnel excavation. This has the excellent effect of shortening the stop period as much as possible, thereby shortening the construction period and reducing the survey cost.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing a button bit at the tip of a rod of a rock drill.

FIG. 3 is a perspective view illustrating a core bit according to an exemplary embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of a core bit according to an embodiment of the present invention.

[Explanation of symbols]

 1 Face in front of the ground 2 Drilling hole 3 Rock drilling machine 4 Bit R rod 10 Core bit 11 Bit 12 Core sleeve 13 Joint sleeve

Claims (1)

[Claims] 1. A bit at the tip of the rod of the rock drill is replaced with a core bit capable of sampling during or after the drilling of a drill hole for explosive loading in the rock front rock mass. Then insert this core bit into the hole,
A geological survey method for a rock excavation method in which a core core is rotated by driving a rod of a rock drill to extract a rock core from the rock in front of the rock face for investigation.