'The diversity is what makes it so fun, every job is different'

On water, on rails, narrow dikes, buildings, basements and rough terrain. Geotechnical consulting firm Lankelma has a lot of equipment in house to do soil testing. Director Gerard Lankelma of Lankelma Ingenieursbureau: "If there's a place where it wouldn't be possible, we'll make it happen."

Gerard Lankelma is the fourth generation of a family-owned soil testing company. "We are a geotechnical consulting firm and in 2021 it will exist no less than 125 years. We deal with probing in the broadest sense of the word; for the purpose of subsurface stability, to calculate the bearing capacity of piles and sheet piles, but we also perform soil mechanical calculations. We work with a staff of consultants: employees in the field and the inside staff who calculate data and process it into reports." 

The name Lankelma is no stranger to the world of probing. "Our working area is the whole of the Netherlands and we have several branches. I myself work from Purmerend and twenty years ago I founded the Oirschot, Almelo and one in the United Kingdom branches. They now work autonomously and where possible we work together, we don't bite each other."  

Its rich history in the field of soil and everything related begins with the establishment of the soil drilling company in 1896. "The Lankelma Group developed into an expert in many fields; activities such as soil drilling for source gas, water supplies and later foundations. In addition, ground investigation, probing and drilling emerged, which is now the central activity. We also focused on making soil mechanical calculations and advice. From this came Lankelma Ingenieursbureau, an independent consulting firm that developed into a renowned company. Quite soon the environmental engineering consultancy was established, offering various products in close cooperation with the engineering firm and groundwater engineering. We have a lot of equipment in house to carry out soil investigations; in addition to the well-known Tracktruck, a CPT truck with a tracked undercarriage, we have a pontoon for CPTs it on the water, a truck for CPTs on rails, a small tracked truck for CPTs on narrow embankments, where the maximum allowable mass applies, and we have CPT devices for CPTs in buildings and basements. We have supplemented it with sounding trucks with tracks under them that can handle rough terrain just fine." 

The principle of probing is not complicated, according to Lankelma. "We push a probe rod into the soil at the bottom is a probe cone with a top angle of 60 degrees. The penetration force is digitally measured in the cone. This and other data are stored in a computer. In the office, this data is processed into a report. The challenging part is that you can do this for the foundation of a small house, to construction work to move a road. That's fun work, because you never know exactly what you're going to encounter in the ground, especially in the Netherlands; every job is different."