Dry stone. Report of restoration work on two dry stone retaining ramps on agricultural land in the slope at LURS (04) France
The first ramp is located in a place called Lurie, on the western slope of the rocky peak of the village of Lurs (Alpes-de-Haute-Provence). She started from the overhanging communal road and went down to an agricultural plot. This path leading to the village gate has kept its proportions and historical width of mule access. We can note in places the presence of calade and no donkeys. The ramp is as wide as the path which indicates that it must be passable with a hitch. The underlying agricultural parcel was reworked during the construction of a contemporary villa on neighboring parcels. Today an asphalt road access vehicle to the house passes at the foot of the retaining wall of the road. The level was lowered to allow the circulation, suddenly the foundation of the first row of stone retaining the ramp is now overhanging and barefoot It can be noted the presence of a very large hutch on the plot formerly served by the ramp This type of hutch is often linked to grapevine cultivation on very stony soil but only a cadastral search would verify it. The hillside is little planted with olive trees, it is populated with almond trees http://unepierresurlautre.wordpress.com author Louis Cagin t2046 Constructive method of the ramp: The cut of the support that we were able to take up during the restoration shows that the profile of the hill was little overcast at this place. The rock outcrops and dives quickly. The layout of the ramp was based on the original floor of the rocky slope on which the path passes. It is remarkable that the ramp was finally built by adding stone fill. On this embankment, once the level reached, was installed a calade that is still in place. We have already met this same process at Lurs during one of our restoration work. The retaken wall was on the same slope and also supported an old road. Fig 3 Another example of road support The support can be divided into four different areas for the laying of stones: -1 the facing area where the largest stones are placed in an average particle size of 20 to 50 cm; larger modules are reserved for the bottom of the wall and the crown (ZAP in Fig. 4) -2 the fitting area of the back of the wall where are placed the stones without faces with an average particle size of 20 to 12 cm (ZAA in fig.4) -3 the drain zone where are placed the stones without faces with an average particle size of 4 to 15cm (ZD in fig.4) -4 the embankment zone which is different from the drain in that the stones are not fitted (ZR in fig.4) We believe that these developments, which require large volumes of stone, were made possible by the activity of the local quarries located at the bottom of the hill, which had to produce abundant, inexpensive material and close to amenities. Fig.4 cut of the layout Fig.5 cut of the wall Fig.6 the other restored wall http://unepierresurlautre.wordpress.com author Louis Cagin t2046 Fig.7 after intervention The second ramp is on the opposite side of the peak rocky Lurs, it is dedicated to the olive, the road is also called the rise of olive trees. The ramp in question is also a field access, the difference lies in the fact that the field overlooks the path. The access is at the foot of a very old whitewashed wall that could be a door or frame left in the outpost of the village. During the excavation we exhumed a shard of glass (to date at the analysis) which seems medieval XV-XVI. The path is today one of the accesses arranged to allow the vehicles to arrive in Lurs. During the work we found a terminal surrounded by remnants of calades that indicate the level of the path before its modernization. We took care to leave these remains in place. Fig.8 The terminal It is not the same stone as that of the previous restoration, its origin is micro-local, including the cliff overlooking the site. In fact the equipment is of a completely different nature (fig.9). The availability of stone is reduced and the available grain sizes are more homogeneous. So the profile of the wall also varies in order to adapt to the available stock. The wall is very wide at the bottom and is reduced quickly, it is triangular Fig.9 cut of the wall http://unepierresurlautre.wordpress.com author Louis Cagin t2046 The stock of stone is of average grain size between 15 and 30 cm with a few rare blocks larger, the rest is composed of smaller volumes of 8 to 15cm; no gravel or aggregates, the rest of the ground floor when working is only clay soil
Louis Cagin
