What are the drilling inspections and allowable deviations in drilling construction?

(1) After the final hole and hole cleaning, the hole diameter, hole shape and inclination should be measured by special instruments, and when the above instruments are lacking, the outer diameter d is equal to the bored pile reinforcement cage.

The diameter plus 100mm (but not greater than the diameter of the drill bit), the length of not less than 4-6d steel bar detector is hoisted into the hole for testing, and the test results should be reported to the supervision engineer.

Review. (2) If defects are found after inspection, such as inconsistent center line, exceeding the vertical line, decreasing diameter, elliptical cross-section, boulders in the hole, etc., these defects should be reported in writing to the supervising engineer, and appropriate measures should be taken to correct them.

3) When the inspection confirms that the hole meets the requirements, the hole inspection form should be filled in immediately, and the next process construction can be carried out only after the supervision engineer signs it.

4) The longitudinal deviation of the pile position is not more than 50mm, and the transverse deviation is not more than 100mm.

<>1.After the final hole and hole cleaning, the hole diameter, hole shape and inclination should be measured by special instruments; When the above-mentioned instrument is lacking, the outer diameter d is equal to the diameter of the bored pile reinforcement cage plus 100mm (but not greater than the diameter of the drill bit), and the length is not less than 4-6d of the reinforcement hole detector is hoisted into the borehole for detection, and the test results should be reported to the supervising engineer for review.

2.If defects are found after inspection, such as inconsistency in the center line, exceeding the vertical line, reduction in diameter, elliptical cross-section, boulders in the hole, etc., the contractor shall report these defects in writing to the supervising engineer and take appropriate measures to correct them. The contractor shall bear the repair measures and costs.

3.The permissible deviation of the borehole shall be in accordance with the provisions of Table 405-2.

Answer: b

This question examines the cause of the deflection of the borehole. Drilling deviation: the site is too flat and compact, the drilling rig is uneven or uneven settlement occurs during the drilling process; The drill pipe is bent and the gap between the drill pipe joints is too large.

Options A, C, and D will cause the hole to deviate from the direction of drilling.

Summary. In the drilling work, it is encountered that the hole depth correction is required when the borehole depth deviates from the design depth. 1. Drilling depth correction before starting the well:

When the drilling depth deviates from the design depth, reasonable technical measures need to be taken to accurately correct the drilling depth. 2. Upward extension borehole depth correction: When some rock strata and hydrological characteristics are found during the drilling process, the borehole depth must be adjusted according to the actual situation to ensure the accuracy and safety of the borehole.

3. Depth correction when the borehole is stagnant: when the borehole is stagnant, the new borehole depth must be determined according to the actual situation.

In the drilling work, it is encountered that the hole depth correction is required when the borehole depth deviates from the design depth. 1. Drilling depth correction before starting: when the drilling depth deviates from the design depth, reasonable technical measures need to be taken to accurately correct the drilling depth.

2. Upward extension borehole depth correction: When some rock strata and hydrological characteristics are found in the drilling process, the depth of the borehole with traces must be adjusted according to the actual situation to ensure the accuracy and safety of the borehole. 3. Depth correction when the borehole is stagnant:

When the borehole is stagnant, a new borehole depth must be determined based on the actual situation.

4. Depth correction when the borehole deviates from the target area: when the drill hole deviates from the target area, correct technical measures must be taken to determine the drilling depth to ensure the accuracy and safety of the drilling quasi-cong wheel. 5. Rest assured well depth correction:

When the depth of the reassuring well does not conform to the actual situation, the correct technical measures must be taken to determine the reassuring well depth.

The purpose of the requirements for borehole oblique is mainly to ensure the smooth running of the pipe and the normal operation of the deep well pump of this bench for pumping. According to the specification, when the hole depth is less than 100m, the hole inclination shall not exceed 1°, and when the hole depth is greater than 100m, the maximum hole inclination shall not exceed 3°.

In general, the hydrogeological borehole design document should be prepared according to the drilling task and the technical requirements of the above-mentioned boreholes. The content of the design document generally includes: hole depth, diameter of opening and final hole, position of hole body travel reducer, position of water-stopping section and water-stopping method, filter type and location, drilling method and technical requirements, etc.

The plan for the removal of the drilling fluid should also be accompanied by the stratum lithology profile of the design borehole, the wellhole structure profile and the location map of the borehole plane.

Accurately marked.

Before drilling, you should first be familiar with the requirements of the drawing and process the benchmark of the workpiece; The flatness of the general datum and the perpendicularity of the adjacent datum. According to the location and size requirements of the drilled hole, use the height gauge to draw the cross center line of the hole position, and the lines are required to be clear and accurate; The finer the line, the higher the precision. Because the line of marking always has a certain width, and the general accuracy of the line can be reached, it is necessary to use vernier calipers or steel plate rulers for inspection after the line is drawn; If the inspection after marking is not enough, the workpiece with the wrong line is often drilled, and the position accuracy of the hole cannot be guaranteed at all; Especially in the examination room of grade identification, due to the psychological tension of the students and the fear that the workpiece can not be completed on time, they are often anxious to drill the hole without inspection after the line is drawn, and it is too late to find that the position accuracy of the hole is out of tolerance.

Therefore, it is necessary to develop a good habit of checking after the line is drawn.

Draw a test square or test circle.

After the line is drawn and the inspection is qualified, the inspection square or inspection circle with the hole center line as the symmetrical center should also be drawn out, as the inspection line when the test drilling is used, so that the drilling can be checked and borrowed from the drilling position, generally several inspection squares or inspection circles of different sizes can be drawn, the small inspection square or inspection circle is slightly larger than the drill bit cross blade, and the large inspection square or inspection circle is slightly larger than the diameter of the drill bit.

Answer]: b2021 p362 2020 p357 2019 p359

This question examines the reasons for the deflection of the borehole caused by the cherry blossoms. Drilling skew: poor site flatness and compactness, uneven installation of drilling rigs or uneven settlement during drilling; The drill pipe is bent and the gap between the drill pipe joints is too large.

A. Rotten C and D options will cause the borehole to deviate from the drilling direction.