Soil nailing is a ground stabilization technique that can be used on either natural or excavated slopes. It involves drilling holes for steel bars to be inserted into a slope face which are then grouted in place. Mesh or shotcrete is attached to the bar ends to hold the slope face in position.
Soil nailing is commonly used as a remedial measure to stabilize steep sloping embankments. Other applications for soil nailing include:
- Temporary excavation shoring
- Tunnel portals
- Roadway cuts
- Under bridge abutments
- Repair and reconstruction of existing retaining structures
- Landslide redemption
- Steep cut stabilization
- Long term stabilization to existing structures without the need for demolition
The main considerations for deciding whether soil nailing will be appropriate include; the ground conditions, the suitability of other systems to perform the same task (ground anchors), geosynthetic materials, and finally cost.
Soils which are particularly suited to soil nailing include clays, clayey silts, silty clays, sandy clays, sandy silts, sand, and gravels. Soil nailing can be used on weathered rock as long as the weathering is even throughout the rock.
Soils which are not well-suited to soil nailing include those with a high groundwater table, cohesion-less soils, soft fine-grained soils, loose granular soils, and ground exposed to repeated freeze-thaw action.
Some of the advantages of using soil nailing include:
- They are good for confined spaces with restricted access
- There is less environmental impact
- They are relatively quick and easy to install
- They use less materials and shoring
- They are flexible enough to be used on new construction, temporary structures, or on remodeling processes
- The height is not restricted
Limitations of using soil nailing include:
- They are not suitable for areas with a high water table
- They are not suitable for permanent use in sensitive and expansive soils
- Specific contractors are required.
- Extensive 3D modelling may be required.
Long-term performance monitoring is typically implemented to collect data to ensure adequate performance and refine future design practices. Parameters to be measured include vertical and horizontal movement of the wall face, local movements or deterioration of facing elements, drainage to the ground, loads, load distribution and load changes in the nails, temperature, and rainfall.
Soil nailing, in many cases, provides a cost-effective solution to steep slope erodibility problems throughout the construction process. It is an often forgotten about remedial practice that is both functional and environmentally friendly. Keep it in the back of your mind as a topic of discussion with your engineer the next time you’re between a rock and a hard place.
Wasn’t George Washington a land surveyor? Yes, he was. There are many people in history who were surveyors who went on to do great things. In fact, Mount Rushmore in South Dakota features the faces of three land surveyors. George Washington, Thomas Jefferson, and Abraham Lincoln were all land surveyors at one time or another. Theodore Roosevelt is the only non-surveyor on that mountain. I don’t know how he got on there …
I want to put a fence up around my property. Should I get a boundary survey? Yes, you absolutely should have a boundary survey done of your property to ensure that your fence does not encroach onto your neighbors’ properties.
What is involved in performing a boundary survey? There are several steps involved in properly performing a land boundary survey: First, we go to the Recorder of Deeds Office in your county and get a copy of the deed for your property as well as the deeds for all of the properties that surround yours. If those deeds mention any subdivision plans, we retrieve a copy of those plans as well. Second, we enter the descriptions of those properties into our Computer Aided Drafting (CAD) software and piece them together like a giant, mathematical, jig-saw puzzle. Third, we send a crew to your property to look for and recover any existing property markers in your neighborhood. Once the crew has found sufficient evidence of where the property lines are, they will set any missing corner markers on your property and set stakes along the lines for your fence to follow.
That sounds like a lot of work. What if I only want one (1) of my lines staked? In order to properly determine the location of any one particular line, it is still necessary to survey the entire area. A typical situation that can arise is as follows: The deed for your property says that you own 200 feet along the road in front of your house. Our crew goes to your site and recovers 2 iron pins in the areas of your front corners. After taking careful, precise measurements, the crew determines that the distance between the 2 existing iron pins is 199 feet. This is 1 foot shorter than the 200 feet called for in your deed.
So, now the crew is faced with a dilemma. Is one of the pins in error by 1 foot? Is the other pin in error by 1 foot? Are both pins in error by ½ foot? Is one pin in error by 9 inches and the other by 3 inches? You can see that the possibilities are seemingly endless. This is why a competent land surveyor will survey, not just the 1 line, but the entire neighborhood around your property to make an accurate determination of where, on the ground, your property lines are located. That way, in the end, not only will you be satisfied, but your neighbors will be happy as well.
I see land surveyors looking through a big camera on a tripod. Doesn’t that tell you where the property lines are? First of all, it is not a camera. It is purely a measuring device called a Total Station. It is very much like the instruments used by the three fellows mentioned above who are on Mount Rushmore. It measures angles from 0 degrees to 360 degrees in the horizontal plane. It also measures angles from 0 degrees to 360 degrees in the vertical plane. This is where the similarities to the old instruments end. The modern version also measures distances using an Electronic Distance Measurer (EDM), or laser. Surveyors record these measurements and use them to perform their calculations.
If you have any other questions or concerns, kindly contact Howell Kline Surveying, LLC at your convenience. One of our friendly, dedicated professionals will be happy to discuss your needs!
Rain rain go away! With each storm that hits Chester County our phones ring more and more. Drainage problem after drainage problem seems to be appearing out of nowhere. Homeowner’s yards with rivers in them, driveway stream crossings washing out, videos of basins filling up with water. Could it be possible that these are all drainage “problems”? Of course not! These drainage “problems” are the direct result of record rainfalls for the last 2 years. Currently, Chester County is approximately 75% ABOVE it’s average rainfall for the year. That is a massive amount!. And it isn’t just the rain. The ground is so saturated that infiltration has been so diminished that nearly all of the rainfall that comes out of the sky is hitting the ground and running off. And yet, everyone wants to point the blame at their neighbor, PENN DOT, their Township etc. rather than blaming the true culprit…..Mother Nature. That is right, Mother Nature is currently giving us a pretty good ass whipping and she shows no signs of letting up. So….what can be done you ask? Well, a few things actually. First and foremost is that one must recognize that about 75% of these “problems” are not problems at all. For example, a river of water flowing through your yard on it’s way to a stormwater facility is not a problem. With a lot of rain, you have to expect a lot of runoff. If your house is not being flooded out or your yard isn’t being eroded than you don’t have a problem. If you don’t care to see water running through your yard when it rains then buy a house on top of a hill. Secondly, with these extreme rainfall amounts one also must consider that older communities were not designed to handle such events. We classify storms by intensity and frequency of occurrence. For example, a 2 year storm is a storm with such intensity that it is expected to occur once every 2 years and a 100 year event is a storm with such extreme intensity that it is expected to only occur once every 100 years or so. The problem is, Mother Nature is sending us rain events of 2, 5, 10 and even 25 year frequencies every few WEEKS! Many older communities were simply not designed to convey stormwater for these large events and further compounding this problem is severe lack of maintenance of these pipe systems. Many are clogged, collapsed and in disrepair. So….how can THAT be fixed? Short answer, not easily. It requires money, lots of money. A few municipalities have now formed Stormwater Authorities and are collecting a fee (not a tax!!) from property owners based upon their area of impervious coverage. Will this new “fee” fix these problems? That remains to be seen and I for one am skeptical, sorry. So…my best advice, unless you want to spend 10’s if not 100’s of thousands of your own dollars, is to grin and bear it and keep telling yourself….this is noooooo problem!
All developers are aware of the dreaded bog turtles. However, there may be some that are unaware of endangered plants located in our area. The serpentine barrens are distinctive terrains located in our area that are underlain by the rock serpentinite. These barren areas consist of sparse, grassy vegetation with scattered trees. In addition, they consist of uncommon plants in Pennsylvania.
A Pennsylvania Natural Diversity Inventory (PNDI) will have to be conducted if your project requires it. You may be subject to a hit from the PA Department of Conservation and Natural Resources (DCNR) if your project is located within or near this terrain. The DCNR will then issue a list of the potential plants that could exist on the property which include the Serpentine Aster, Annual Fimbry, etc. If so, the next step would be to hire a biologist to survey the property to determine whether the listed plant species exist on the property. This may sound like an issue that can easily be resolved; however, the plants can only be identified during their flowering times. The flowering times range from about a five-month period all the way down to a two-month period. Some species have flowering times during the months of August and September which could cause significant delays in construction.
The DCNR will issue a clearance letter if they determine that the plant species of concern do not exist on the property. If they are identified on the property within the proposed ground disturbance area, then the DCNR will simply remove them from the property prior to construction. If they are identified on the property outside of the ground disturbance area, then the DCNR will ask the property owner to be involved in a habitat management plan to protect the plants.
Please contact D.L Howell to determine whether a PNDI will need to be performed for your property and we’ll be glad to assist you.