2009 Field Note 1 - Saving the Fort
Fixing the gap on the corresponding gap on the exterior in 2007, and a good thing too!
The temporary supports were still doing their job, but there was clearly not a moment to spare.
While clearing the foundations we encountered the cutting for a Late Period burial and what are perhaps the last two bricks of the original interior façade still in situ (arrow).
Within the southern gap, a lateral corridor hollowed out in the center of the wall made a complicated repair even more difficult!
Sparrows making a home in the Fort
The scratching of little feet for millennia has created the large holes in the upper walls of the Fort.
Resurfacing the interior walls to support the top-heavy upper walls and stop the cycle of deterioration.
At the end of the 2008 season, we made a heroic effort to shore up (at least temporarily) the heavily damaged and collapsing central portion of the west wall--the only wall that is more or less intact along its entire length. Steel and timber supports were installed to hold it over the summer when it became clear that the central portion of this massive wall was settling into the great "central gap" hollowed out of its interior face. We had already filled the corresponding gap on the exterior but with nowhere else to go, now the wall was moving to settle into the deep and extremely fragile gap on the inside. Increasing cracks had made it clear that if this were allowed to continue, a massive collapse was all too likely, so we stepped in to try to stop this 9 m high, 5 m thick, and 67 m long wall in its tracks.
Returning in late January 2009, were we anxious to see how successful our attempts to halt the downward trajectory. The beginning of the season greeted us with a few isolated fallen bricks but no new major cracks--and no catastrophic collapse. It was with much relief we could see that our efforts to brace the wall had worked, but the strain on some of the beams was obvious. Had we not erected the temporary shoring, we would have had a much different and less welcoming reception. But there was little time for congratulations--now we needed to begin the permanent filling of the ugly gaps with new mud brick and to stabilize the wall as soon as possible.
Our steel and timber braces allowed us to work in safety in the critical zone, as we prepared the ground for the new brickwork required. We were well aware that all areas of collapse have a corresponding area of compromised foundations below them (i.e., pits--made by animals, archaeologists, or looters--now filled with sand). In the case of the interior central gap, archival photographs showed Late period (post-1000 B.C.) burials were to blame. These had been cut into the walls at foundation level and then exposed by Garstang's 1905 excavations. As always we prepared a small area for foundation reinforcement--about 1.5 m long--and filled it with silty soil compacted in layers with water to make a hard ground surface. During this procedure we re-encountered the cuttings for these burials, and in the small space between two of them, we uncovered what may be the last two bricks of the original interior surface of the wall still extant and in situ, the rest of the wall surface having eroded away over the millennia. This discovery helped us to calibrate just how far out from the surviving wall face we should begin to rebuild the wall when filling the gap.
Building the buttresses or columns of brickwork over the reinforced area to incrementally fill the gaps and implement the permanent repairs
The pizza oven method of delivering bricks into the lateral corridor
The pizza is ready! The lateral corridor is consigned to the pages of history!
The remains of matting between the courses of the first phase wall Matting was used to provide strength through thick walls in many ancient Egyptian mud-brick structures.
Matting made of juncus reeds was used frequently to line Predynastic graves, as in this well-preserved example in the worker's cemetery at HK43, at Hierakonpolis.
Once an area of foundation reinforcement dried and hard, we built a buttress, or column of bricks extending upward to support the upper walls, first at the sides of the gap to provide much need additional stability. Only then did we felt comfortable about really entering the breach. We plan to build successive buttresses that will be joined together and thus form a solid infill to repair and "complete" the wall.
Fixing the deep and rather frightening recesses within the gap was every bit of the challenge we feared it would be. The southernmost of the two recesses that make up the "central gap" included a lateral "corridor" extending southward for more than 10 meters through the core of the wall. Since we had put in the bracing, we could finally, but cautiously, enter the cavity and find out just how scary it was.
With the jacks supporting the so-called roof of the gap, we began clearing away the fallen debris. This allowed us, for the first time, to get the measure of this gap. The tape measure doesn't lie, but we had to suspend belief when we reeled it out to more than 3 m. Peering in, we could now see clearly that the first phase wall at its core had been completely breached, and the back wall of the gap was actually the the inner face of the second phase wall cladding the exterior. Careful scrutiny revealed the way the bricks were laid to fill in between the pilasters of the first phase wall. In this way that we knew it was actually not a bricked up doorway, but just a deep and ugly hole.
Slowly we realized what a truly precarious state the Fort had been in. Between the gap on the exterior wall (which we filled and repaired in 2007) and this corresponding gap on the interior, there had not been 1.5 m of wall as we had originally supposed, but actually only two brick length--in other words, only 52 cm, holding up the entire west wall! Luckily we had repaired the exterior gap first, giving the wall the 1.5 m of support we thought it already had!
We needed to fill this gap fast, but before we could do so, we had to deal with the lateral corridor. This was accomplished by Richard positioning himself in the cavity of the southern gap so as to be just one leap away from safety if anything started to shift. So positioned (and pretty uncomfortably), Richard then flung mud into the corridor by the handful followed by brick fragments. Once nicely coated, whole bricks were slid into place on a plank using the "pizza oven" method that had proven so successful in previous seasons. Using this method the corridor was eventually filled solidly and consigned to the archives with a stout masonry wall. Once accomplished, our mason, Abdullah Nour, gradually filled in the cavity under careful watch for any brick fall from overhead. What a relief when that gaping hole was reduced to a mere overhang a few bricks deep!
One unexpected benefit from a minor loss of bricks from the corbelling ceiling of the gap was the exposure of ancient reeds laid in a horizontal layer between the courses of brick of the first phase construction. These reeds added strength through the width of the wall, the way geotextiles are used today. Reeds and matting were used in the construction of the funerary enclosure of Khasekhemwy at Abydos and other large mud-brick construction throughout Egypt, but similar mats had not previously been observed in the Fort with certainty. Now the reason became obvious--elsewhere the core wall had not been breached, so its interior make up was unknown, and as the cladding walls of the second phase is only about 1 m thick, matting was unnecessary at lower levels, but was no doubt used higher up where it is difficult for us to see. The first reeds to be found in situ within the Fort's construction, samples were taken and identified by our staff archaeobotanist, Ahmed Gamal Fahmy (University of Helwan, Cairo) to be of juncus, a marsh plant used frequently in the Predynastic period for matting, especially to cover the bodies for burial.
In its weakened state, the Fort is a very delicate creature. Slight movements in the segments along its 67 m course cause cracks within the monolithic masonry of the upper walls. These cracks are transmitted downward causing minor cracking of the cladding walls of the second phase, and gradually these bricks begin to slough off. Perhaps just one or two bricks at a time, but it adds up and thus the holes form and the corbelling of the brickwork begins as more and more bricks fall prey to gravity leaving the fully bonded upper walls less and less well supported.
These cracks are very inviting to sparrows who love to roost even on the tiniest ledge. It is entirely possible that the scratches of little feet are responsible for the large holes in the upper walls, worn smooth by the feet of millions of birds over a 5,000-year period. Wasps are another vector of destruction. They enter cracks and hollow out nest areas just behind the facade. Although the wall may appear sound, eventually the outer bricks will erode away leaving a surprising large hollow behind.
In response to these issues, we have begun to resurface the damaged areas of the interior to support overhanging walls, plugging the holes and forcing the sparrows to relocate!
This was just the first two weeks and we made better progress than envisioned. Our big gaps are now only half of their original size and have lost their ability to frighten us. The Fort's movement has been stopped in its tracks and we can finally sleep soundly at night!
The problem half solved. The central gaps are filling up!