What is the proper vinyl sheet pile driving method for different soil types?

“Pitch and drive” method is the most practical way of pile driving in loose soils especially when using short piles. Also called “set and drive”, this method installs piles one by one. However, with only one interlock in control, sheet piles have high tendencies of rotating from the axis and leaning forward or backward. Panel driving is recommended for the dense deposit of sands and compact cohesive soils such as heavy clay or in presence of obstructions. In this method, a number of piles are interlocked together before driving. The panel of piles is supported by guide frames and driven gradually in sequence, sometimes in a staggered manner. The method can achieve installations of longer piles in more difficult ground conditions with better results in sheet pile alignment and verticality. In cases of difficult ground conditions such as hard strata and the presence of obstructions, driving assistance is employed along with a proper selection of driving method and equipment. Jetting and drilling help by loosening or eliminating obstructions by creating pressure right under the tip of the sheet pile being driven. Long and slender PVC sheet piles require steel mandrels as supports when driven in such conditions. Mandrel, which shape is similar to sheet pile profiles, increases the rigidity of Plastic Sheet Pile and supports the weight of the driving equipment such as a vibro-hammer.

What is the proper machine to drive piles in different conditions?

Impact driving is suitable for all soil types but appears to create the highest degree of stress to sheet piles. It is more appropriate to cohesive soils and soft soils such as silts and peats, loose medium to coarse sand, and gravels free of rock inclusions. Drop hammers such as the hydraulic hammer are the common types of impact-driving machinery. Driving using vibratory hammers is ideal for non-cohesive or granular soils such as soft soils and round-grained sand or gravel. It has also shown satisfactory performance in sandy, silty, or softer clay soils. It is less effective in angular-grained materials and soils with a firm consistency. With the introduction of vibration, however, the sub-soil can be further compacted, increasing penetration resistance and ultimately-refusal. If this is the case, driving aids like jetting and drilling might be necessary.

What are the pvc sheet pile selection criteria for soil condition of different hardness?

General rule of the thumb: “the harder the soil, the stronger and stiffer sheet pile section should be used”. Driveability of a pile section is a consequence of its cross-sectional properties (thickness, depth, and width), designed shape, length, grade, and the applied load. Hardness of soil strata characterized by SPT or CPT values is used to predict soil resistance which is essential in the calculation of driving force to be applied. Knowing the range of force from the selected driving machine, corresponding sheet pile sections can be picked according to their yield strength and elastic modulus.

How should I choose a sheet pile section for soils with, say, SPT Value, N=30? Can I still consider using vinyl or shift to steel?

Every sheet pile material has a design purpose, strengths, and areas of improvement. The availability of different materials denotes the need for a special material for a specific application. Plastic or synthetic sheet piles for example are known for being light and corrosion-resistant; Steel sheet piles are recognized for their extraordinary strength and versatility; and so on.

Vinyl Sheet Pile Installation

Vinyl Sheet Piling or PVC Sheet Piles are an effective alternative to steel sheet piling for bulkheads, seawalls, cut-off walls containment barriers. The main advantage of vinyl sheet piles is the superior corrosion resistance when exposed to seawater, where no oxidation occurs. Vinyl sheet piles are also highly resistant to marine borers which make it superior to wooden solutions.

Driving any sheet piling material to significant depths is a challenging task. In installing vinyl sheet pile the several conditions should be considered such as the concerns of drivability, high blow count soils, possible underground obstructions and driving to extreme depths.

Installation tools for vinyl sheet piling are generally dependent on the soils being driven into. In sandy soils tools such as water jets, vibratory hammers, air hammers, and rail jets are often used. In cohesive clays and silts drop hammers, vibratory plate compactors, and backhoe buckets are generally the tools of choice.

At greater depths or in the case of hard ground, a steel guiding sheet pile is used. ESC vinyl sheet piles can easily be combined or connected with other construction materials. The sheets can be glued, welded, sawn or drilled. Wood, concrete, steel or plastic can be used as a cap and wale system. The application of waling with anchoring is also possible.

Hammering is the most commonly used method, in which sheet piles are mechanically embedded into the soil along the pre-installed templates with the use of vibratory hammers, i.e. light equipment with small impact energy. In the case of hard, dense surfaces, or when long elements need to be hammered, steel mandrels are used. Mandrels are special guide bars of a shape and length reflecting the used PVC elements. Mandrels allows installation of long profiles even up to 12m, it helps removes obstacles found in soil, it helps maintains straight lines installation ensuring pre-loosening of soil which significantly accelerates installation work.

If soils are too hard or dense, an impact hammer can also be used to complete the installation. At certain sites where vibrations are a concern, the sheets can be hydraulically pushed into the ground.

Jetting is used in cases of very compact or cohesive soil where the force of vibration hammers is not sufficient to embed the vinyl sheet piling to the required depth. Jetting consists in exerting pressure directly under the sheet piles which are being installed, which helps loosen and remove the soil or the obstacles. Special water or air ejectors are used in this technology.

Digging method is used when the constructed walls are not embedded too deeply into the ground and it consists in the PVC piling being installed in a ditch which is subsequently filled in with a bedding layer selected individually to best meet the requirements of a given project.

GLOBAL PILING SOLUTIONS PROVIDER

Change Language :

Vinyl Sheet Pile Installation