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The Evolution Of Jet Grouting Technology

Jet grouting, a ground improvement technique utilizing the scouring power of water, has a long and fascinating history. While water excavation methods have been used since ancient times, documented use in the mining industry during the Middle Ages highlights its early application. In the 1950s, the first jet grouting patent was filed in England, but it was in Japan where the true practical development of the technique took place.

Initially, jet grouting aimed to enhance water tightness in chemical grouting by eroding untreated or partially treated soil and replacing it with cement-based slurry. This innovation led to the creation of thin cut-off walls and derivative applications that sealed gaps between declutched sheet piles. The evolution continued as rotating jet grouting emerged in the early 1970s to address the limitations of panel jet grouting in terms of varying thickness and fragile strength. By the mid-1970s, jet grouting had been exported to Europe and gained popularity worldwide.

During this period, three main variants of jet grouting emerged based on the required geometry: the single system (S), the double system (D), and the triple system (T). The single system involved fluid grout erosion and mixing with the soil, while the double system introduced compressed air to enhance the erosive effect, especially below the water table. The triple system utilized grout, jetting water, and compressed air to achieve erosion and grout injection independently, offering advantages in fine-grained and cohesive soils.

The 1980s marked a significant period of experience and confidence in jet grouting, leading to a wide range of applications. Since the early 1990s, advancements in jet grouting methods have resulted in larger treatment ranges and column diameters, driven by cost and program considerations. These developments allowed for the construction of columns with diameters exceeding 5 meters, even reaching 9 meters in softer ground. The increased flow rates and higher pressures provided by improved equipment played a crucial role in achieving this.

However, the results of jet grouting can vary depending on equipment and soil types, presenting challenges in finding exact solutions. The late 1980s witnessed the introduction of colliding jet grouting, where dual jets limit the eroding capability and achieve precise intended diameters. This innovative concept, known as "crossjet grouting," improved design quality. Further evolution of colliding jetting included the deep mixing method, expanding the range of application and enabling optimal interlocking.

Jet grouting gained acceptance and popularity globally, with widespread use in Europe, the United States, Canada, and South America. It became recognized as a reliable geotechnical tool, finding applications in foundations, excavations, tunnelling, water barriers, slope stabilization, and underpinning existing foundations.

Today, jet grouting stands as one of the most common ground improvement methods, providing convenient and cost-effective solutions to various geotechnical challenges worldwide. Its evolution continues, driven by ongoing technical developments and the contributions of pioneers in the field. As jet grouting's capabilities expand, its impact on the construction industry remains significant.
Jet Grouting