How soil pushes (and how to build a wall that pushes back)

When you contemplate the retaining wall you're about to build, you may imagine how firm and solid it'll appear from the front, or how great the new garden will look above it. But unless you give serious thought to what goes on behind and below the wall, it may not look good for long. A poorly built wall can lean, separate, even toppleand it's out there in plain sight where all your neighbors can point and snicker. You don't want that!

Lots of people think a retaining wall needs to hold back all 6 gazillion tons of soil in the yard behind it. It doesn't. It only needs to retain a wedge of soil, or elongated wedge of soil, similar to that shown in Fig. A. In simple terms (our apologies to all you soil engineers out there): Undisturbed soilsoil that has lain untouched and naturally compacted for thousands of yearshas a maximum slope beyond which it won't hang together on its own. This slope is called the failure plane. If left alone, the soil behind the failure plane will stay put on its own. But the soil in front of the failure planethe natural soil or the fill you're going to addwants to slide down the failure plane.

Gravity, along with the slope, directs most of the weight and pressure of the fill toward the lower part of the retaining wall. Since soil weighs a beefy 100-plus lbs. per cu. ft., you need some pretty heavy materiallarge retaining wall blocks, boulders, timbers or poured concreteto counteract the pressure. Just as important, it needs to be installed the right way. Here are three key principles in building any solid retaining wall:

A retaining wall only needs to hold back a wedge of soil, not everything behind the wall.

A retaining wall needs to retain all the material that fills the space between itself and the failure planethe steepest angle at which existing soil can hold itself together before caving in.

Water can weaken retaining walls by washing out the base material that supports the wall (Fig. E). But far more frequently, it causes problems by building up behind the wall, saturating the soil and applying incredible pressure. That's when walls start leaning, bulging and toppling. Well built walls are constructed and graded to prevent water from getting behind the wall and to provide a speedy exit route for water that inevitably weasels its way in.

Take a look at the well-drained wall in Fig. D. The sod and topsoil are almost even with the top block, so surface water flows over the top rather than puddling behind. Just below that is 8 to 12 in. of packed impervious soil to help prevent water from seeping behind the wall. The gravel below that soil gives water that does enter a fast route to the drain tile. And the perforated drain tile collects the water and directs it away from the base of the wall, escorting it out through its open ends. There's nothing to prevent water from seeping out between the faces of the blocks, either; that helps with the drainage too. The wall even has porous filter fabric to prevent soil from clogging up the gravel. What you're looking at is a well-drained wall that will last a long time.

Now look at the poorly drained wall in Fig. E. There's a dip in the lawn that collects water near the top of the wall. There's no impervious soil, so the water heads south, slowly waterlogging and increasing the weight of the soil packed behind the wall. The homeowner put plastic against the back of the wall to prevent soil from oozing out between the cracksbut it's also holding water in. Yikes! There's no drain tile at the bottomthe trapped water can soak, soften and erode the base material. Not only that, an excavated trench that extends below the base lets water soak into the base material and weaken it. You've got a retaining wall that has to hold back tons and tons of water and saturated soiland when that water freezes and expands in the winter, matters get even worse.

A well built wall starts with a solid base.

Here is the original post:
How to Build Retaining Walls Stronger: The Family Handyman

1 hour 6 minutes ago by Jacqueline Quynh - KPAX News

Every spring we watch the rivers around Missoula rise - and for some of us homeowners we're watching how close water is getting to our backyards.

Sometimes the only thing stopping a rush of mud and water is a wall... So what if that retaining wall fails?

Nate Williams rents an apartment next to Rattlesnake Creek.

"It's a very clean water stream," said Nate Williams, who lives near the creek.

He likes the location for it's access to fly fishing, but the creek can also get very fast, and very high during the spring -- making it at times a threat.

"I have seen the river come up within 8 inches of the support beam," said Williams.

In some places the only thing to stop the water is a retaining wall. And in one area, underneath the bridge on East Front Street in Missoula, the retaining wall is badly deteriorating.

"Trees have grown up and broken loose the concrete," said Williams.

"You can tell how old this bridge is because this plaque here tells us it was built in 1932 but not the case for the retaining walls and structures below it."

Original post:
Crumbling retaininer walls worry Missoula residents

Retaining Wall Backfill Walmart 2
Back filling the retaining wall behind the Choctaw Wal-mart for Phaze Concrete. The project consisted of placing 8000 tons of rock behind the wall that wrapp...

By: CAD Oklahoma

Read the original post:
Retaining Wall Backfill Walmart 2 - Video

Riverfront Restoration - Township Presentation 2013 - Safety Rail Request
Presentation for the Township Board 11-19-14 requesting consideration of a grant for a safety railing. Presentation for the Riverside Preservation Commission 11-14-14 for a permit to install...

By: Riverside #39;s Riverfront

Go here to see the original:
Riverfront Restoration - Township Presentation 2013 - Safety Rail Request - Video

Stone Slinger Backfilling Retaining Wall Walmart 1
CAD Oklahoma back filling the retaining wall behind the Choctaw Wal-mart for Phaze Concrete. The project consisted of placing 8000 tons of rock behind the wall that wrapped around the west...

By: CAD Oklahoma

Link:
Stone Slinger Backfilling Retaining Wall Walmart 1 - Video

Brick Retaining Wall Brisbane Call LandscapersBrisbanecom on 07 3053-5664
Brick Retaining Wall Brisbane Call LandscapersBrisbanecom on 07 3053-5664.

By: Michael Landscaper

More here:
Brick Retaining Wall Brisbane Call LandscapersBrisbanecom on 07 3053-5664 - Video

Crazy Los Angeles car accident sees vehicle lose control and land hanging off a wall
A car lost control and spilled off the road and landed on a wall in Los Angeles Sunday. According to an NBC news report, the vehicle skidded up the concrete retaining wall after losing control...

By: TomoNews US

See the article here:
Crazy Los Angeles car accident sees vehicle lose control and land hanging off a wall - Video

CLEAR LAKE | This one of North Iowa's 50 Things is referred to by some residents as "Clear Lake's front yard."

The Clear Lake Sea Wall was a project of the Works Progress Administration (WPA) completed on July 1, 1936.The WPA was established by President Franklin D. Roosevelt in response to the Great Depression.

The split-boulder retaining wall was commissioned by state conservation officials and constructed by workmen from a transient camp located north of Mason City.

The site along the lake in downtown Clear Lake was home to the White Pier Amusement Park until it was destroyed by a wind storm in 1931.

The Sea Wall is dotted with benches for visitors to stop and enjoy looking at the lake dotted with boats.

The location is home to the Lady of the Lake and many community events including the Color the Wind Kite festival, Lions chicken BBQ, and the Seawall to Seawall run set for Aug. 30.

The area was recently a subject of controversy as a group sought to place a veteran's memorial along the Sea Wall. The Clear Lake City Council voted not to place that memorial on the Sea Wall. But the council did vote to form a task force to select a new location for a veteran's memorial which could include the Sea Wall.

Peggy Senzarino

More here:
No. 17: Clear Lake Sea Wall

Home | Back

August 25th, 2014 6:24 pm by Rain Smith

Updated at 10:35 p.m.

KINGSPORT An elderly woman has been killed after crashing through the carport of her Kingsport home, sending her vehicle over a retaining wall and into Fort Patrick Henry Lake.

The incident occurred at about 3:55 p.m. on Monday.

Based on a preliminary investigation, Kingsport police believe Inez N. Summers, 92, was driving a 1998 Lincoln Town Car into the driveway of her residence, 3743 Hemlock Park Circle.

For unknown reasons, according to the Kingsport Police Department, Summers lost control of the sedan, entered the carport and overrode two metal retaining posts. The Lincoln then exited the rear of the carport and continued down an incline at the back of the home, crossing a retaining wall and splashing into the lake.

Kingsport police say a neighbor called 911 to report the crash.

Summers' car was submerged in the lake, with divers recovering her body within an hour. She was the sole occupant of the vehicle, police said.

Police say the actual cause of death has yet to be determined and an investigation is continuing.

Link:
UPDATE: Vehicle crashes into Fort Patrick Henry Lake; one dead

Sacred Space August 13th, 2014
The Bridge Community Church in Arnold, MO took two days and restored a retaining wall for a family in need. Scripture says that we are to be the hands and feet of Jesus, and one of the ways...

By: Josh Massey

Read this article:
Sacred Space August 13th, 2014 - Video