Applications in Geopolymer: Compromised Soil

Welcome to our series on applications in geopolymer injection, where we invite technical experts from around the globe to share applications and use cases where geopolymer injection worked to solve critical challenges when nothing else would.

This month’s expert is John Silva, National Director of Operations for Geobear USA. With more than 20 years in the ground engineering industry, he brings with him a wealth of expertise in geopolymer injection, ground stabilization, and various methods of increasing ground strength.

Q: Today, we’re going to talk about a utility project. John, can tell us about a project that really stands out as an innovative, effective use of geopolymer in utility applications?

One of the projects that really stands out to me is for a local city water district. The city was planning on upgrading an old water pumping station and had to dig up multiple large diameter pipes. The pipes were buried about ten feet down and ran underneath the foundation of a heavy CMU wall. Engineers began soil testing and found the soil was compromised from previous water leaks.

Q: What kind of concerns or potential issues did the compromised soil cause?

Engineers were concerned that the compromised soil could slough in or collapse on itself, putting work crews at risk. Moreover, they were concerned that further excavations near or under the wall would compromise the foundation of the wall. They had the general contractor put the excavation on hold until a solution could be found.

Q: How did you get involved in the project?

The city’s engineers approved a plan utilizing geopolymer injection. Geobear came in to support the general contractor and help address concerns about compromised soil. Our team worked with city engineers to execute the plan as approved. The geopolymer would be used to reinforce and stabilize the surrounding soil to prevent issues.

Q: It seems like a complex environment. What was the solution you utilized to address the complexity of the situation?

Our team installed metal tubes to strategic depths along both sides of the proposed excavation. Geopolymer was injected through these tubes from a depth of 10’ to the surface. This created 3D coverage in the soil so that, once excavated, the remaining side walls would be effectively glued together – preventing sloughing or collapse.

Q: How did the project work out? Was the contractor able to resume the project?

The project was successful, and the contractor was quickly able to resume the rest of the project. The contractor reported that excavations were completed without issue and the wall stood solid. In fact, the general contractor was awarded additional work due in part to how successfully this was handled.

Q: What is one of the biggest thing you want other engineers or contractors to know?

Today, more and more engineers are learning about the different applications of geopolymer injection. The first step is awareness that the technology exists and has been around for over 50 years. It’s a proven, effective technique. For engineers and contractors alike, it’s important to stay educated on the different applications and how those applications can help in a variety of challenging situations.