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Slope Restoration Design

For more than 15 years, we have performed mitigation for landslide and failed slopes throughout Southern California. From small backyard repairs using an engineered heavy duty pipe and board system, repairing a slope using structural geosynthetic reinforcement (GSR), retaining walls, or installing caissons and grade beams for more extensive landslide repairs...we are the answer.

Typical Slope Restoration Repairs

Information for Homeowner/Private Projects
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WHAT IS A SLOPE FAILURE OR LANDSLIDE?

Slope Failure

The downward and outward movement of a mass of soil beneath a natural slope or other inclined surface; four types of slope failure are rock fall, rock flow, plane shear, and rotational shear

In other words, a slope failure is a phenomenon that a slope collapses abruptly due to weakened self-retainability of the earth under the influence of a rainfall, saturation or an earthquake

Landslide

Sudden downward movement of a mass of soil from a cliff or steep slope.

Landslides happen when a slope becomes unstable, usually because the base has been undercut or because materials within the mass have become overly saturated with moisture.

HOW TO IDENTIFY THE SIGNS OF A SLOPE FAILURE?

The first sign of trouble - A tension crack

There are occasions when a landslide or slope failure gives no warning or sign of an impending catastrophe.  Many times a failed slope does not ‘just happen’ overnight, but a tension crack will develop in the slope.  A tension crack is a void or fissure that normally runs parallel to the slope face.  They can be 20 feet to hundreds of feet long and can have gaps of ‘normal’ looking slope surface in between.  What is happening is a slide plane is developing below the surface, and the tension crack is usually the first sign of a failure.  Below are some other signs to look for:

  1. Is the slope eroding and sloughing off in large chunks because of the angle or height of the slope? This can affect structures nearby. Gravity will try to correct a slope angles greater than 45 degrees. Look for fresh erosion in large sections.

2. Look at any trees on the slope. Are they growing straight or are they leaning downhill? Leaning fences, walls or vegetation means there is soil movement.

3. Look for water springs seeping out of the mountain movers…almost always a problem!

4. Look for “steps” of soil down the slope. This is where chunks of earth have broken loose in the past and moved partially down the mountain movers and stopped.  This is a dead giveaway.  Usually tenskion cracks are visible and a ‘head-scarp’ is developing.

5. Any movement of the slope will create havoc with any structures within the slide plane of the slope failure. The depth of the failure and accessibility will determine the method of stabilization and repair.

Slope stability/slope performance concerns most mountain movers property owners. Heavy winter rains resulting in saturated earth materials can cause slope failures, landslides, and settlement. If such an event occur, the Department of Building and Safety typically issues an “Order to Comply”. This may require a repair, acceptable to the Grading Division, within a specified period of time. Gravity and the lack of friction will typically reduce the gradient of most slopes; therefore, a steeper slope is more prone to instability and failures. Recent erosion and/or tension cracks in the exposed soil, parallel to the contours, may be indicative of recent slope movement or may precede slope failure. Leaning trees and curved trunks indicating that the tree has tried to right itself during growth, may be indicative of a long-term soil movement process called “downhill creep.”