Crawler Mounted Drilling Rigs Construction Skills

Sep. 11, 2020

Crawler Mounted Drill Rig Supplier to share this article for you.

1. Rig inspection

1. Pour grease into each lubrication point.

2. Check the hydraulic oil level and oil quality, check the gear oil level and oil quality of the hoist, powerhead, and slewing gear reducer.

3. Check the engine oil level and oil quality, and check whether the filter needs to be replaced.

4. Check whether the drill teeth need to be replaced and whether the opening and closing of the drill bucket are normal.

5. Check whether the actions of the drilling rig are normal.

Second, the drilling rig is in place

1. Extend the crawler of the drilling rig and lock the left and right walking frames with pins.

2. Drive the drilling rig to a position near the pile position. The working plane of the drilling rig is required to be solid and flat, and the car body to be level. If the slope is too large, it can be adjusted with sand and gravel; if the ground is too soft, steel plates can be laid under the crawler of the drilling rig to ensure the stable operation of the drilling rig.

3. The hole position of the drilling rig's rotation interval should be between 3.8m-4.5m. If allowed, the luffing cylinder will raise the boom and mast to a high position as much as possible, so as to reduce the impact of the drill's own weight and the lifting and lowering alternating tension on the hole.

4. Make sure there are no obstacles within the gyration radius of the drill.

5. Operate such actions as turning on the car, telescopic luffing oil cylinder, and mast sag adjustment to perform accurate alignment so that the head of the drill is directly at the marked point of the pile.

6. After accurate alignment, the rotation is cleared, the drill head is dropped to the same plane as the upper edge of the protective tube, and the drilling depth is cleared.

Three, drilling

1. Drill into the clay layer

(1) The clay layer is characterized by high viscosity, impermeability, and low drilling resistance;

(2) During the drilling operation, the output torque of the control powerhead should not be too large, and control the operating handle to appropriately increase the powerhead speed, generally 8-20r/min;

(3) Keep pressing to make the drill teeth cut into the clay layer;

(4) The footage depth of a single bucket is determined by the diameter and height of the drill bucket. When the pile diameter is above 800 mm, the footage is 50-70% of the capacity of the drill bucket; when the pile diameter is below 800 mm, the drill bucket footage The amount shall not exceed 50% of the capacity of the drill bucket.

2. Drilling into the sand layer

(1) The characteristics of the sand layer are no cementation, strong water permeability, low compressibility, and high drilling resistance;

(2) During the drilling operation, it is necessary to control the powerhead to output high torque and low speed, and the control pressure method is point pressure;

(3) When drilling large-diameter pile holes, it is better to use a double-bottom sand dredging bucket. The depth of the single bucket should not be too deep. The drill bit should be lifted and released slowly and evenly to avoid buried drill accidents to a large extent.

Note: Eighty percent of buried drill accidents during the construction of crawler mounted drilling rigs occur in the sand.

Crawler Mounted Drilling Rigs

Crawler Mounted Drilling Rigs 

3. Drill into the pebble layer

(1) Pebbles are mechanically loose formations, with the characteristics of large pores, strong water permeability, low compressibility, and high shear strength;

(2) During the drilling operation, the drill teeth are rotated to cut into the pebble gap to squeeze the stones into the drill bucket;

(3) Low speed and high torque should be used when drilling to prevent mud from scouring the hole wall at high speed;

(4) Strictly control the depth of single bucket footage;

(5) Lift and release the drill bit as slowly as possible;

(6) Layers with large gravel content can be drilled with double-layer rock-socketed drills, and the stratum containing boulders and boulders can be processed by short spiral drill bits, and then use rock-socketed drills to harvest after loosening;

(7) In a dense pebble layer, drill at a slow speed, use the main hoisting wire rope to suspend the drill rod, use the gear to move the pebble, and use the method of alternating forward and reverse rotation. When the forward rotation encounters greater resistance, Immediately reverse, and then forward again, the cycle repeats, loosen the pebbles and then float down the drill pipe;

(8) If the footage is fast, it is necessary to maintain a heavy-load drilling state through point pressurization, no back pressurization, and no continuous pressurization. If you do not advance for a long time, in order to prevent the hole from collapsing, you need to raise the drill bit for a while, lower it again, and re-establish free surface drilling;

(9) The hook of the bucket bottom mechanism for opening and closing of the drill bucket is easy to be stuck by the pebbles and fails, and there is also the possibility of unhooking at the bottom of the hole.

(10) If it is not closed, when using the sand bucket, close the bucket door completely every time to ensure that the hook is completely hung to prevent the bottom of the bucket from opening in the hole;

(11) Check gears and drill pipe safety pins every time when dumping slag, and replace worn and broken gears in time.

4. Drilling into mudstone formations

(1) Mudstone is a kind of sedimentary rock formed by the solidification of mud and clay. It is not bedding and lumpy. It is mainly composed of fine-grained sediments. It has high cohesion and low compressive strength, generally between 0.17-10Mpa. It has strong water absorption and cementation;

(2) Machine lock rods are generally used, and friction drill rods are sometimes limited by pile depth;

(3) The drill teeth are staggered, with an angle of about 53°;

(4) When using friction rods, pressure should be continued. After cutting into the stratum, the load should be increased, and then continue to drill. Adjust the pressure amplitude by the size of the load, so that the drill teeth can cut into the original rock formation and always maintain the cutting state;

(5) The pressurization method needs to be controlled when the machine lock lever is used. When the front of the crawler is about to be supported by pressurization, it means that the pressurization is too rapid or does not advance. At this time, the pressurization cannot be continued, and the reason should be determined;

(6) If the formation does not change much, the drilling time and depth of each bucket should be within a certain range, and the depth of the single bucket in the mudstone layer should be 40cm;

(7) When the bottom of the bucket is closed by reversing, try to prevent the bottom of the bucket and the drill barrel from reversing together when there is a load when drilling. The reversal should not exceed two turns. Too much reversal will flatten the steps of the hole and increase the difficulty of drilling the teeth into the native rock formation next time.