Foundation · How trenchless works
Trenchless Boring Methods: HDD, Auger Boring & Microtunneling
Trenchless construction installs underground utilities without trenching the surface above them. There isn't one trenchless method — there are several, and choosing the right one for the crossing is where the cost and the risk are decided. Here's how the methods we run compare and when each one wins.
The methods, in plain terms
Horizontal directional drilling (HDD) is steerable and surface-launched: a drill head follows a designed, curving profile under the obstacle, then the product pipe is pulled back through. It suits long crossings, curved paths, and anywhere you can't disturb the surface.
Jack and bore — auger boring — is pit-launched and straight: a steel casing is jacked through the ground on a fixed grade while an auger clears the spoil. It's the standard for short, grade-accurate cased crossings under roads and railroads.
Microtunneling is the large-diameter, high-precision option: a remotely operated, guided boring machine installs bigger pipe on tight line and grade, often for deep gravity sewer where accuracy is non-negotiable.
How to choose
The crossing decides the method. If the path needs to curve or the run is long, HDD. If a railroad or highway requires a straight, cased crossing on grade, jack and bore. If the line is large-diameter or has to hold an exact gravity slope, microtunneling. Where the surface can be opened and restored cheaply, open-cut is still the lowest-cost answer.
Soil matters as much as the method. West Texas caliche, limestone shelves, and clay each change the tooling, the speed, and the risk — which is why we scope the ground before we recommend an approach.
At a glance
Method comparison matrix
| How the trenchless methods compare | Directional Drilling | Jack & Bore / Auger | Microtunneling | Open-Cut |
|---|---|---|---|---|
| Launch | From the surface | From a pit | From a shaft | Open trench |
| Steerable | Yes — curved paths | No — straight | Yes — guided | — |
| Grade accuracy | Good | Excellent | Highest | — |
| Typical diameter | 2″–24″+ | Casing to spec | 24″–120″+ | Any |
| Best for | Long / curved crossings | Short cased road & rail | Large / deep gravity mains | Open ground, easy restore |
| Surface disruption | Entry / exit pits | Pits only | Shafts only | Full trench |
Diameters and uses are typical ranges; the right method is decided by the crossing, the soil, and the spec.
Choose a service
The methods we run
Horizontal Directional Drilling
Long or curved crossings under roads, rail, and rivers
View service →Jack and Bore
Short, straight cased crossings under road & rail
View service →Auger Boring
Grade-critical cased crossings in stable ground
View service →Microtunneling
Large-diameter, deep, on-grade gravity mains
View service →Pipe Bursting & Pipe Lining
Replacing or rehabbing an existing failing line
View service →Underground Utility Installation
Full-scope water, sewer, gas, electric & fiber
View service →Road, Highway & Railroad Crossings
Permitted cased crossings (TxDOT, UP / BNSF)
View service →Common questions
Trenchless methods — FAQ
What's the difference between HDD and jack and bore?
HDD is surface-launched and steerable — good for long or curved crossings. Jack and bore is pit-launched and straight — good for short, grade-accurate cased crossings under roads and rail. The crossing and the spec decide which fits.
Which trenchless method is cheapest?
It depends entirely on the crossing — length, diameter, depth, soil, and surface restoration cost. We scope each crossing and recommend the method with the lowest total installed cost, restoration included.