Project: Two-storey apartment building
Location: a suburb of St. Petersburg
Year: 2016
Duration: 3 days
Technology: DEEP INJECTION
Stopping the sinking of a pile foundation without excavation
Problem
Horizontal cracks at the bottom of the load-bearing walls and vertical cracks at the corners of the building
Solution
Stabilization of the pile foundation
Problem
Initial data
A new two‑storey residential building has a foundation under the load‑bearing walls consisting of piles tied together by a reinforced concrete grillage. The problem that arose – horizontal cracks at the bottom of the load‑bearing walls and vertical cracks in the corners of the building.
The surveying organisation determined that the defects are caused by uneven settlement of the pile foundation, because the pile lengths were adopted without considering the actual soil properties and the insufficient bearing capacity of the foundation soil, and some of the piles were not even installed. As a result, deformations appeared in the above‑ground structures, which required soil strengthening to stabilise foundation settlement.
Objective
Ensure normal operation of the new residential house in the shortest possible time.
A new two‑storey residential building has a foundation under the load‑bearing walls consisting of piles tied together by a reinforced concrete grillage. The problem that arose – horizontal cracks at the bottom of the load‑bearing walls and vertical cracks in the corners of the building.
The surveying organisation determined that the defects are caused by uneven settlement of the pile foundation, because the pile lengths were adopted without considering the actual soil properties and the insufficient bearing capacity of the foundation soil, and some of the piles were not even installed. As a result, deformations appeared in the above‑ground structures, which required soil strengthening to stabilise foundation settlement.
Objective
Ensure normal operation of the new residential house in the shortest possible time.
The project in detail
Technologies applied
To solve the problem, a measure was applied in the form of strengthening the soil beneath the foundations by injecting polymer mixtures using URETEK technology by the DEEP INJECTION method. Deep injection was carried out in two stages:
Stage 1 – injection of the mixture under the grillage, filling the voids between it and the soil.
Stage 2 – injection of the mixture at different levels along the pile lengths to increase the bearing capacity of the foundation, to enable the foundation to receive the loads transmitted from the building structures, and to stabilise its settlement.
To solve the problem, a measure was applied in the form of strengthening the soil beneath the foundations by injecting polymer mixtures using URETEK technology by the DEEP INJECTION method. Deep injection was carried out in two stages:
Stage 1 – injection of the mixture under the grillage, filling the voids between it and the soil.
Stage 2 – injection of the mixture at different levels along the pile lengths to increase the bearing capacity of the foundation, to enable the foundation to receive the loads transmitted from the building structures, and to stabilise its settlement.
Solution
As a result of the measures taken, a strengthened geotechnical mass was created at the base of the piles with the required strength and deformation properties, capable of bearing the acting loads from the building. Further settlement of the foundation and deformation of the above‑ground structures was stopped.
The work lasted 3 working days. Its quality was controlled by monitoring using a laser level during the work and by dynamic probing after the soil strengthening beneath the foundation. The effectiveness of the adopted measure was demonstrated by the vertical lift of the settled grillage by an average of 4 mm and the levelling of its surface along the entire length.
The work lasted 3 working days. Its quality was controlled by monitoring using a laser level during the work and by dynamic probing after the soil strengthening beneath the foundation. The effectiveness of the adopted measure was demonstrated by the vertical lift of the settled grillage by an average of 4 mm and the levelling of its surface along the entire length.
NAVIGATION
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