Keller ASEAN delivers a broad range of cost-effective and fit-for-purpose geotechnical solutions across the construction spectrum. We provide solutions from industrial, commercial and housing projects to infrastructure construction for dams, tunnels, transportation and water treatment. We are also a specialist in rehabilitation works and the protection of soils and ground water from environmental damage.

Geotechnical Solutions

Soil investigation

Soil InvestigationSoil investigation is a crucial step in all construction activity. Two popular soil investigation techniques are the drilling of boreholes and conducting Cone Penetration Tests. Boreholes allow a variety of in-situ tests to be performed (for example Standard Penetration Tests and vane shear tests) and for samples to be retrieved and sent for laboratory testing. Cone Penetration Tests involve pushing an instrumented cone into the ground for classifying soil and determining engineering parameters.

Piling

Bored-Piling

Bored Piling

Bored piling is a method that involves boring a circular hole into the ground, installing steel reinforcement and filling the bored circular hole with concrete to form a pile. Boring is carried out to the required depth by means of either a crawler crane-mounted rotary boring unit or a purpose-built hydraulic drilling machine. Bored pile foundations are suitable for all types of soil conditions and compared with conventional driven piling methods, bored piling activities generate less noise and vibration.

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Secant Pile

Contiguous Bored Piles and Secant Piles

A Contiguous bored pile wall is an earth retention system formed by installing closely spaced Bored piles, with a small gap between adjacent piles. In contrast, a Secant pile wall is an earth retention system formed by installing overlapping Bored piles. These walls are designed either as cantilevered or with a variety of supports (ground anchors, walers & struts, etc.). Secant piles are usually selected where there are particular concerns about groundwater inflow, i.e. where there is a high groundwater table and permeable soils.

Driven Pile

Driven Piles

Driven piles include precast concrete piles, steel piles, high-strength concrete spun piles and “mini” triangular concrete piles. A special type of driven pile is the iconic Franki pile, an enlarged base, driven cast in-situ pile.

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Deep Vibro techniques

Deep vibro techniques is the name given to a versatile group of ground improvement solutions. These methods are mainly used to increase bearing capacity, reduce settlements, stabilise slopes, and mitigate liquefaction. Powerful depth vibrators are used for three distinct techniques: Vibro Compaction, Vibro Stone Columns (Vibro Replacement), and Vibro Concrete Columns.

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Vibro Compaction

Vibro Compaction

Vibro compaction is a technique that compacts granular soils and rearranges the soil particles into a denser state. Vibro compaction is often used for land reclamation projects or natural sandy deposits.

Vibro Stone

Vibro Stone Columns (Vibro Replacement)

Vibro stone columns are load bearing columns made from gravel or crushed stones, constructed in cohesive soils or granular soils with high fines content. The stone columns improve the shear strength and stiffness of the soil mass. This highly versatile method is often used for embankments, tanks, buildings, materials stockpiles, highway or railway constructions.

 Vibro Concrete Columns

Vibro concrete columns is a method that transfers loads through weak strata to a firm underlying stratum using high modulus concrete columns. It is usually applied if the fine grained subsoil does not provide sufficient lateral support for conventional stone columns. Vibro Concrete Columns consist typically of pumpable concrete. It increases allowable bearing pressure and decreases settlement for buildings, embankments, tanks and other similar structures.

   

Specialist Grouting

Compaction Grounding

Compaction Grouting

Compaction grouting is a solution that can be applied in various fields such as soil improvement, stabilisation and rehabilitation of foundations, and cavity grouting. A stiff grout is usually injected into the soil under pressure and expands forming almost ball-shaped grout bulbs. The soil surrounding the grouted area is displaced and compacted. It can be used to improve both coarse-grained and fine-grained soils.

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Jet Grounding

Soilcrete® Jet Grouting

The jet grouting process, Soilcrete®, is used for stabilisation and sealing of all kinds of soils ranging from loose sediments to clay. The soil around the borehole is eroded with the aid of high pressure cutting jets of water or cement suspension. The eroded soil is rearranged and mixed with the cement suspension. The Soilcrete® process is often applied for tunnel protection, foundation restoration, dam sealing or groundwater exits.

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Permeation

Permeation Grouting

Permeation grouting involves the low-pressure, controlled injection of a suspension into the soil mass, usually to reduce permeability. Depending on the soil, a variety of materials are injected, often through tube-a-manchettes (TAMs). For finer grained silts and sands, chemical grouts are used, while for sands and gravels, cement grouts are used.

Rock

Rock Grouting

Rock grouting refers to the injection of a suspension (usually a cement grout) to seal fissures and channels within a rock mass. The borehole is often drilled into the rock using a down-the-hole hammer, with the grout delivered through a tube with a single packer. Grouting may be carried out “bottom up” (which is generally quicker) or “top down” (usually for fractured rock).

Soilfrac

The Soilfrac® Process

Soilfrac® is a process of controlled fracturing and grouting. Firstly, tube-a-manchettes (TAMs) are installed in the soil layer to be treated. A grout hose equipped with a double packer at the tip is then inserted into the TAM to allow the injection of the Soilfrac® suspension. Fractures in the soil are created which are then filled with grout. This method is usually applied in foundation restoration and protection of structures against settlements.

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Deep Soil Mixing

Deep Soil MixingDeep soil mixing (DSM) is a method that achieves significant improvement of mechanical properties of the existing soil by mechanically mixing it with cement or compound binders. It is typically used for embankments on soft soils, foundation support, protection of excavation pits, stabilisation of slopes, and reduction of liquefaction potential.

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Dynamic compaction and Dynamic replacement

Dynamic CompactionDynamic compaction and Dynamic replacement are ground improvement techniques that involve systematically dropping a heavy ponders, typically 10 to 25 tons, from specially fitted crawler cranes. Dynamic compaction is applied to granular soils and for typical applications is effective to depths of 6 to 10 m. Dynamic replacement is a process of forming large diameter columns in clayey or silty soils, typically to depths of 5 to 6 m. 

Ground Anchors & Micropiles

Ground Anchor

Anchors are stabilization and support elements that transfer tension loads using high-strength steel bars or steel strand tendons. A full-length hole is drilled through the soil and into the bond zone, in soil or rock. The threadbars or strand tendons are placed in the borehole which is then filled with high-strength grout. After the grout has gained strength, the steel is tensioned using hydraulic jacks. Ground Anchors are typically used in deep excavation support systems, for dam stabilization or to resist uplift forces.

Micropiles

Micropiles are small diameter piles, up to 300 mm. These piles are usually heavily reinforced and carry high loads in spite of their small diameters. Micropiles are installed with small and light drill rigs, allowing access into narrow spaces, low headrooms and onto slopes. Typical applications include underpinning of existing structures and construction very close to existing buildings. Ground Anchors and micropiles are installed with similar drill rigs.

Prefabricated Vertical Drains

pvdPrefabricated Vertical Drains (PVDs) are thin elements, typically 100 mm x 5 mm, made of a plastic core and geotextile filter. Using specialized rigs, PVDs are pushed deep into soft soils to aid in the dissipation of pore water pressures and hence acceleration of consolidation settlements. After installation of the PVDs, usually a soil surcharge (called preload) is placed over the area, and consolidation settlements monitored. It is also possible to apply a vacuum pressure to draw pore water out of the soil through the PVDs, in a method called vacuum consolidation.

Foundation Civil Works

Foundation Civil WorkAfter the completion of pile installation or ground improvement, other foundation elements such as pile caps, base slabs, ground beams and load transfer platforms need to be constructed. These elements are needed to properly transmit the load from the superstructure to the foundations.

Testing

TestingVarious tests are performed on piles and improved ground to ensure quality. On piles, static load tests, dynamic tests and pile integrity tests are often performed. For ground improvement an array of tests such as Cone Penetration Tests, coring and unconfined compressive strength testing, plate load tests and water pressure tests are performed, depending on the ground improvement method employed.

Monitoring

MonitoringAfter the foundation is completed, the superstructure can be monitored during construction and during service life. Settlements, tilts, excess pore water pressures, soil movements and other parameters are often measured. This data is then meaningfully plotted and interpreted. In some cases such as Soilfrac compensation grouting, real-time monitoring of the settlements is crucial to the success of the technique.