Mastering the Art of Culvert Elevation: A Guide to Highway Construction Excellence

Today I’m sharing the Excavator construction process of raising the bottom of a culvert on a highway.

The culvert is about four meters high and four meters wide. The construction requirements are to raise the bottom of the culvert by 45 centimeters and dig a drainage ditch of 1.2 meters wide on either the right or left side. The soil needed for raising the height is provided by the construction party and dumped at the entrance of the culvert.


After understanding the construction requirements, the following issues need to be considered:


The excavator cannot rotate inside the culvert, and the soil needed for filling can only be shoveled into the middle of the culvert from the entrance using the excavator bucket. It is necessary to discuss with the construction party about dumping the backfill soil required on both sides of the entrance.


The bottom of the culvert should be fully backfilled and compacted with a track roller before excavating the drainage ditch. If the position of the drainage ditch is not backfilled, the soil on one side of the track will be very loose, not achieving the desired effect.

If the position of the drainage ditch is not reserved and the bottom of the culvert is fully backfilled, consider the solution for the excess soil from excavating the drainage ditch the second time. Here’s what I did: firstly, backfill the bottom of the culvert to raise it by 30 centimeters, then use the excess soil from the second excavation of the drainage ditch on the first 30 centimeters of backfill. This way, the drainage ditch is excavated and the backfill height also reaches the standard.

Without reserving the position for the drainage ditch, after the ditch is excavated, when leveling the backfilled soil the second time, pay attention to the position of the tracks. The area for the excavator to move in is very narrow, and with the increased backfill height, it’s important to maintain a safe distance between the boom and the top of the culvert. Ensure the tracks do not fall into the drainage ditch while moving.

When leveling, find a reference point. I used the trace lines left by pouring the concrete template as a reference. If possible, you can ask the construction party to snap a chalk line as a reference. The height of the chalk line should be thirty to forty centimeters higher than the backfilled height.

Maintain a consistent width for the drainage ditch, which can be measured with a tape measure. When excavating the drainage ditch, keep the soil line on one side parallel to the side of the culvert, so the width of the ditch will be consistent.

Personal protective measures: The air in the culvert is sealed, and the dust is excessive, so it’s necessary to wear a mask, turn on the air conditioning to maintain air circulation, and clean the radiator and air conditioning filter promptly after construction.

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