GROUND IMPROVEMENT TECHNIQUES USING WITH OMS VIBROFLOTS

OMS Pile Driving Equipment GmbH. provides a large selection of ground improvement techniques: “vibro compaction”, “vibro replacement” and “vertical drain”. As effective as our products are, choosing the correct equipment for your project might be a challenge. However, our experts on ground engineering can help you to decide on the best equipment for your project.

Today, the social and industrial growth has increased the importance of ground engineering. In fact, the profession plays a crucial role in projects such as power stations or the expansion of infrastructure systems like harbors and airports. Therefore, it is good to consult to an expert before deciding on the method of ground improvement.

Methods

Deep vibro compaction and vibro replacement methods are mainly to increase the strength of granular soils as well as unfavorable soil conditions. They are also beneficial for the improvement of deformation characteristics of the same type of soil. The two methods work by enhancing the bearing capacity of the weak layer. Then, they utilize the benefit of the improved resistance. Ergo, this results in a transition between deep foundation and soil stabilization. This way, the transition ensures a structural support below or on the improved ground surface both safety and economy wise.

As OMS team, we support our customers by recommending the best soil improvement equipment solutions. Vibro compaction and vibro replacement (stone columns) as well as vertical drain (wick drain) equipment of OMS have proved themselves in the global market from Europe to Middle East, South East Asia and America continent.

VIBRO COMPACTION – TOP FEED GROUND IMPROVEMENT TECHNIQUE

Vibro compaction method is mostly suitable for fine granular soils with seismic risk. For this reason, experts suggest for land reclamation projects to decrease the risk of liquefaction. Furthermore, the technique is useful for the densification of sand-like soils on site through an OMS Vibroflotation prob. Due to the concurrent impact of saturation and vibration, loose sand particles changes into a more compact state. As a result, lateral confining pressure of the sand mass rises.

Vibro compaction top feed technique is convenient for medium to coarse-grained sand with silt content. Cohesive soils with silt and clay does not respond to vibratory compaction. The illustration below explains the operation:

Ground Improvement Technique
tandem-vibro-compaction-technical-drawing

Vibro Compaction

Tandem Free Hanging Ground Improvement:

The tandem vibro compaction includes two vibroflotation probes. Each prob suspends from the same crane. Land reclamation projects that require 20 – 25 m depth uses this configuration. The quality of compaction/stone column is controllable with a data logger supplied by OMS. Thence, the depth, compaction rate, time-related compaction and withdrawals can be measured and monitored. The data logger is also be able to measure the gravel volume.

Single Free Hanging Ground Improvement:

The single free hanging vibroflotation probe consists of the same interchangeable parts as Tandem. The depth of compaction can be deeper. Correspondingly, medium to small scale projects can be executed with a single free hanging system. Compared to the Tandem system, crane capacity of the vibroflotation probe is slightly smaller. Similarly to Tandem, the quality of compaction can be monitored with a “data logger” so that, depth, compaction rate, time-related compaction and withdrawals as well as gravel volume can be measured and monitored.

VIBRO REPLACEMENT – BOTTOM FEED GROUND IMPROVEMENT TECHNIQUE

Vibro replacement stone column is a system where vertical columns that made out of compacted gravels are placed into the soil. This technique builds load-bearing columns and  these columns are made out of gravels or crushed stones in cohesive soil and granular soil with high fines content.

Vibro replacement columns are beneficial for enhancing wide range of soil types. They can improve very soft clays and peat to materials suitable for the vibro compaction method. The equipment of the vibro replacement method is identical to the one in the vibro compaction method. However, vibro displacement equipment is slightly different.

As for the operation of stone/gravel columns, there are two methods: the top feed and the bottom feed. The latter operation will be issued in this part. “The bottom feed” process feeds gravels from the end of the prob with pressurized air. In order to achieve an optimum performance, OMS has developed the vibroflotation probe and gravel hooper with the pressure chamber. Additionally, these OMS vibroflotation probes can mount on an existing drill rig or leader, crane or an excavator.

OMS Bottom Feed Vibroflotation Method
Drill Rig / Leader Mounted Technical Drawing

Vibro Replacement by Stone Columns

Drill Rig / Leader Mounted Ground Improvement:

The OMS vibroflotation probe (bottom feed system) with gravel hooper can mount on an existing drill rig or a leader. For this action, a supervisor from the OMS technical team is needed.  This configuration is useful, because the drill rig or leader equipped with a pull-down system. This system allows an additional pull-down pressure during compaction and penetration.

Bottom Feed Free Hanging Ground Improvement:

The OMS vibroflotation probe (bottom feed system) with a gravel hooper. The system is suspends from a crane. The crane capacity must be able to carry the suspended weights in order for the configuration to work.

Excavator Mounted Bottom Feed Ground Improvement Technique:

This ground improvement technique is easier to mount on a customers’ excavator. In any case, the help of OMS supervision team is needed. Also, it is simpler to operate and cost friendly. However, stone columns comes with limited depth. Excavator selection is crucial in this configuration.

drill-rig-system-technical-drawing