Ground Improvement is used to improve the load bearing capacity of soils as an alternative to more costly structural foundation systems. MRCE has successfully implemented ground improvement to provide structure and earth support in challenging site conditions. MRCE founding Partner Daniel Moran pioneered the modern industry of ground improvement in 1929 when he invented and patented sand drains for stabilization of soft ground.
- Ground Improvement Techniques
MRCE engineers evaluate, select, and design ground improvement methods to address subsurface conditions and site logistics. MRCE also designs ground improvement for Contractors using their proprietary tools and methods and performs mix design and mix testing in our laboratory. Ground improvement can provide economical construction solutions for challenging site conditions and budget constraints. MRCE has experience with a full range of ground improvement techniques including:
- Deep Soil Mixing
- Stone Columns
- Rigid Inclusions or Controlled Modulus Columns
- Dynamic Compaction
- Pre-compression using Surcharge and Vertical Drains
- Cement stabilized soil
- Reinforced earth and GRES
Grouting can improve the strength, stiffness and water tightness of in-situ soils and rock. Proper selection of grout type and control of grout pressures and volumes are important to successful grouting without damaging adjacent structures. Grouting techniques that MRCE designs include:
- Compaction grouting for void filling, ground improvement, and settlement compensation
- Permeation grouting using particulate (cement / microfine cement) and chemical grouts
- Chemical grouting
- Jet grouting and jet grout structures for load support
- Rock joint grouting
Amtrak Bridge over the Thames River
Construction of a new railroad bridge lift span was halted when a caisson experienced unexpected settlement. MRCE, in collaboration with Amtrak and the bridge construction team, diagnosed the cause and crafted a unique deep grouting program to place more than 1 million gallons of microfine cement grout to successfully stop the movement. The MRCE design used deep tube-a-manchette pipes to control grout placement, and real-time computer monitoring to control grout injection. Confirmation borings demonstrated successful permeation of the microfine cement grout and compressive strengths from 500 to 1500 psi. This inventive approach stabilized the existing foundation, extending its life and supporting the new lift bridge.
HRSD Atlantic Treatment Plant Expansion
This $150 million treatment plant expansion increased plant capacity by 18 million gallons per day and presented a unique challenge because the existing plant remained operational during construction. MRCE’s subsurface investigation, testing and engineering design employed pre-loading to improve soft compressible soils for plant support. This ground improvement allowed the use of shallow foundations instead of deep pile support saving considerable cost and time. 40 foot high surcharge fill was placed adjacent to operating plant structures without impacting existing structures. The surcharge fill slopes were designed using mechanically stabilized earth (MSE) to increase load at the perimeter of the fill and prevent damage to existing structures. Underpinning and jacking was designed to support utilities below the surcharge fill.