Installing new underground utilities is essential for keeping the modern economy operating. However, the process can be disruptive. Trenching often means ripping up entire streets and sidewalks, closing them off to traffic, and introducing fall hazards.
Therefore, learning how to get utility installation right is essential. Here’s everything you need to know.
What Is A Trench?
The U.S. Occupational Safety and Health Administration (OSHA) defines them as an excavation made below the surface of the ground that is narrow in relation to its length. The depth of a trench is always greater than its width and does not exceed 15 feet when measured at the bottom. (When you think about the needs of utility installers for long cuts, this makes sense).
How Does Soil Type Affect Utility Trench Installation?
Before beginning any digging, contractors must consider the soil type. That’s because the soil type affects trenching difficulty.
Clay-containing soils can be more problematic to dig and require more powerful equipment. When they get wet, the challenge increases further because of the increased water weight.
Sandy soils are more straightforward to dig than clay soil types. However, trench walls are more prone to collapsing and can cave in.
In some circumstances, contractors encounter rock. Digging through it requires special drilling techniques or blasting.
Naturally, the cost of trenching increases when:
- The soil’s stability is poor and requires supports
- The ground is difficult to break through, like rock
- The soil is impermeable, forcing contractors to implement surface stormwater runoff solutions
Soil Classifications
The construction sector classifies soils into various categories, depending on their composition. Classifications run from the most stable to the least stable. Solid rock won’t move without specialist tools, while sandy or gravelly soils can collapse readily, hampering construction work.
- Stable rock. A thick rocky surface with minimal soil component.
- Type A soil. Includes silty clay, sandy clay, claw, and clay loam.
- Type B soil. Includes silt, silt loam, gravel, and soils near fissures or sources of vibration.
- Type C soil. Includes sand and gravel.
Soil type matters for safety reasons. A cubic foot can weigh more than a ton (depending on the type), harming workers if it falls on them.
It can also affect construction work. Soil conditions will dictate your material choices.
Dry And Wet Utility Installation
You will also need to consider the type of utility installation you want to perform. Trenching requirements vary considerably.
Dry utilities include electricity lines, fiber optic and broadband cables, natural gas lines, and telephone wires. Wet utilities include waste water drains, mains water supplies, and storm drains.
Dry utilities generally require less material excavation and shallower trenches than wet utilities. As a result, their environmental footprint is reduced, and contractors often find planning and installation to be more straightforward. However, gas and electrical safety codes and regulations are extensive, potentially making permitting and dry utility design to be more challenging.
Utility Installation Pre-Planning
Laying new utility lines is a complex and challenging process. Therefore, careful planning is required to reduce legal liabilities, costs, and disruption in the community.
Critical elements of utility installation pre-planning include:
- Defining the scope of the installation project, including the infrastructure you will install, the permits you need, and the deliverables required
- Studying various soil reports, site plans, groundworks surveys, and utility maps to characterize the soil’s existing condition
- Applying for permits and ensuring approvals within necessary timeframes
- Building links with qualified contractors who understand utility works
- Creating safety protocols for various stakeholders, including those on-site
- Establishing contingency plans if you cannot lay cables in their original location
- Identifying risks, such as weather conditions, soil type, and equipment issues
- Establishing communication channels between different stakeholders, including utility providers
The Challenges Of Utility Installation
However, even with the best preparation, utility installation remains challenging. It involves more than merely digging a ditch and lowering various pieces of hardware into it. Several confounding factors can undo even the most experienced professionals. Challenges include:
- Issues with the soil, including sandy varieties prone to collapse
- Unforeseen obstacles underground that conventional surveys don’t highlight in the preparatory phase
- The presence of existing utilities prevents work from proceeding at pace
- Trouble obtaining the proper permits or following building site regulations
- Difficulties with the weather due to rain or extreme temperatures
- Problems getting the necessary trenching equipment onto the site
- Surface and stormwater management and runoff issues
Get Assistance With Utility Trenching Today
Because utility installation is challenging, it pays to work with experts. Muller, Inc. boasts extensive expertise in wet and dry utility installation across Virginia, Maryland, and Washington, DC. With a deep understanding of the region’s soil characteristics and the typical challenges encountered in utility projects, Muller is well-equipped to assist. Reach out to our team today for support with your wet or dry utility projects.