Description
There are a at least 5 eroded areas adjacent to the easement between the storm water channel and my property line. Please have someone come assess the land stability and propose a solution for long term repair. My neighbor has already submitted the same type of request. My property is worse. Thank you for your follow up.
3 Comments
Acknowledged Sarasota County Contact Center (Verified Official)
DHines1951 (Registered User)
Lorraine Damico (Registered User)
Formal Report from Anticus Engineering, a geotechnical engineering service:
The depressions/raveling conditions generally extend to depths ranging from approximately 3.0
to 7.0 feet below existing grade within the upper sands, within the areas tested. Once the soils
grade into denser clayey sands and clays, the conditions are not favorable for raveling due to the
affinity of clay to water and the consistency/density of the clayey material.
In our opinion, the proposed shallow (24 inch deep) interceptor drain system will not be effective,
as water and soil particles will still be able to move toward and through the rip rap. Additionally,
concentrating water along a trench interceptor drain may, in fact speed up the process of raveling
by adding additional water load into a concentrated area.
We would recommend using a chemical grouting program to mitigate movement/raveling of soils
through the rip rap slope. The purpose of the chemical grouting would be to mix with the existing
soils and create a “wall” of stiffened soil parallel and just in front of the rip rap wall; with the “wall”
initiating from the clayey sand layer (with the top of the clayey sand layer ranging from
approximately 5 to 6 feet below grade within the borings completed) upward.
7.1.1 Chemical Grouting Program
We recommend that the area in the vicinity of the slope be remediated using a chemical grouting
program.
Chemical grouting will be used to mix with the insitu soils to densify and consolidate the
sandy subgrade soils to reduce the risk of further migration/raveling of sand into the canal.
It is estimated that approximately 1,400 pounds of chemical grout materials will be
necessary to densify the shallow soil. We would recommend that 70 chemical injection
point locations be installed at 35 locations and that approximately 20 pounds of chemical
grout be injected at depths of approximately 3 and 6 feet below ground surface and within
2.5 feet of the northern site boundary. We would recommend the use of 486 STAR
chemical grout [or engineer approved equivalent] for injection at the approximate point
locations indicated within the Chemical Grout Plan as illustrated on Sheet 2.
We would anticipate that drilling the holes for the grout injection would be completed in
one day and that the injection would be completed in one day. Holes for grout injection
should be approximately 2 inches or smaller in diameter (single injection point diameter is
on the order of 5/8 inch).
The chemical grout pins should be installed to depths as indicated within the plans and
specifications or as indicated by the engineer of record in the field.
We would estimate the cost of the chemical grouting program to be on the order of $8,000.00 to
$14,000.00, with engineering oversight to be on the order of $1,000.00 to $2,000.00 for a total
cost of remediation estimated to be $9,000.00 to $16,000.00.
After completion of the grouting program, the yard area should be regraded as necessary, with
compacted clean (less than 12% silt or clay) SAND to SAND With Silt (SP/SP-SM) [classification
in accordance with the Unified Soil Classification System (USCS)]. Compaction should be
completed in 6 inch loose lifts and compacted to a minimum density of 95% of the Modified Proctor
maximum dry density. After regrading, sod, plantings and associated hardscape may be re-laid,
as necessary.
THE FULL REPORT INCLUDING DIAGRAM AND SPECIFICATIONS IS AVAILABLE AS A PDF FROM THE HOME OWNER AND ANTICUS ENGINEERING (813-642-3965)