Pile Driveability

STEEL SHEET PILES

There is a variety of steel piling plant available on the market to install steel sheet piles. The following tables from the ArcelorMittal Piling Handbook 9th Edition provide useful preliminary guidance on installation methods to consider in predominantly cohesionless and cohesive ground.

Tables 11.2. and 11.3. give guidance on methods to consider for soil types, Table 11.4. takes into account resistance effects from strata thickness. Table 11.5. gives guidance for press-in piling by pitch and drive only. The selection of a suitable pile section for driving into cohesive soil is a complex process and the section choice is often based on previous experience. However it is possible to assess the driving resistance using the surface area of the piling profile and the characteristics of the cohesive strata. The following table may be used for preliminary assessment.

SPT value	Vibro drive	Impact drive	Press-in singles (with jetting)
0 -10	Very easy	Runaway problem => use vibro method to grip pile	Stability problem & insufficient reaction
10 - 20	Easy	Easy	Suitable
21 - 30	Suitable	Suitable	Suitable
31 - 40	Suitable	Suitable	Difficult => consider pre-auger
41 - 50	Very difficult => consider pre-auger	Suitable => consider HYS	Difficult => consider pre-auger or crush piler
50+	Very difficult Pre-auger essential	Suitable => require HYS	Very difficult => crush piler required

HYS: High Yield Strength Steel
Table 11.2. Driving in coarse soils or predominantly cohesionless ground.

Cᵤ value (kPa)	Vibro drive	Impact drive	Press-in
0 - 15	Easy	Runaway problem => use vibro method to grip pile	Possible stability problem & insufficient reaction
16 - 25	Suitable	Easy	Easy
26 - 50	Becoming less effective with depth	Normal	Normal
51 - 75	Very difficult	Normal	Normal
76 - 100	Not recommended	Suitable => drive in pairs	Difficult
100+	Not recommended	Suitable => essential to drive in pairs	Difficult => consider ground pretreatment or jetting

Table 11.3. Driving in cohesive strata.

It is rare to have a site where the ground is classified as wholly cohesionless or wholly cohesive and hence the selection of plant must be a compromise, choosing plant suited to the dominant soil type but also considering the ability of the plant to penetrate the other soil type. The final selection of driving plant and section size for economical pile installation is often based on previous experience. It is recommended that advice is sort from an experienced steel piling contractor.

Further tables and explanation on driveability are also provided in the ArcelorMittal Piling Handbook 9th Edition.