Deep high precision vertical holes in China! Guiyang Nanming Engineering Monitoring Co., Ltd.

Deep high precision vertical holes in China!Guiyang Nanming Engineering Monitoring Co., Ltd.

Domestic deep vertical holes are located in the warehouse base of Guiyang Nanming Engineering Monitoring Company, Guizhou Province. As the experimental hole of drilling deviation rectification Lilun, they have been constructed to 202 meters. The diameter of drilling holes is 225 mm. The maximum deviation value of four directions of the depth plane of any hole is not more than 25 mm. Now they have been constructed to more than 200 meters, reaching 202 meters (the deviation data are as follows). After 202.4 meters, they continue to drill up to 300 meters for water. Well usage.

In the field of dam monitoring, the verticality of high-precision vertical holes, called inverted vertical holes or vertical holes, can not be simply calculated by the deviation of holes (Figure 1 below). The deviation can only be a broad theoretical value, and the most important index is the effective aperture value of the whole hole. (Fig. 2)

Effective aperture: It refers to the measurement of hole inclination X and y by means of elastic middleman plus floating body method (Fig. 3). Establish a plane coordinate system at the orifice. (Fig. 4) Measure one value x and Y per meter or 2 meters from the orifice or the bottom of the orifice, and draw the garden with the diameter of the borehole. So every meter or 2 meters, the garden is projected to the hole plane. The effective aperture is the tangential garden intersected by N (hole depth) gardens. Figure 2 shows the Red Line Garden. Therefore, the deeper the hole is, the smaller the deviation of the four directions of the hole is, and the more vertical the hole is.

The inclinometer data table is as follows:

Fig. 3

  Fig.4

What we want to emphasize here is that the spring in the elastic guide should be close to the hole wall, and the measuring line should be in the center of the elastic guide. The measured value must be one hole inclination per meter or 2 meters continuously. It must never exceed 3 meters, because 3 meters inside the hole is possibly S-shaped. In the course of construction, the construction personnel of our company strictly follow the prescribed anti-inclination measures and methods, and take anti-inclination as the main and meticulous operation. Every drilling footage of 1.0-2.0 m must be measured once, and the situation in the hole must be grasped at any time. If the deviation exceeds the prescribed value, the deviation must be rectified.

The backfill method and displacement method are effective in rectifying deviation. After more than twenty years'construction experience, the company has verified the method of rectifying deviation with hole depth over 177 meters in this experiment. At present, the company holds the technology of tightly rectifying deviation as an effective and successful method. It has been used in our company for twenty years, and the company has completed the inverted and vertical holes of major hydropower stations in the country in the past twenty years. High-precision drilling with double-mark inverted sag. For example, the inverted vertical holes of the world's tallest double-curvature arch dam (Jinping Hydropower Station in Sichuan Province is the world's tallest double-curvature arch dam) are more than 2,000 meters, and the deepest hole is 139 meters deep in the 16 dam sections on the right bank. It is the deepest and most accurate drilling hole used in dam monitoring. It remains to be seen whether we can apply for the world Guinness World Record when we reach 200 meters.