Forces Operating on a laying are perceived mainly by a stone, as a solution in a laying less prochen, than the stones connected by it. Stones well resist only to compressing efforts and, to use this property, them have in a laying according to rules razrezki.
In order to avoid a bend and skalyvanija stones stack one on another so that they adjoined, probably, bolshej the area - the greatest sides. So, if the stone A (fig. 9,) at packing B leans against a stone only in two points under the influence of external loading R .on can cave in and even to break (fig. 9, ). the Stone A can and not receive a break but as pressure from it is transferred only in two points in them stones And and can be shattered. Therefore for uniform transfer of pressure from one stone it is necessary for another, that each of them leant on underlaying not in separate points, and all surface of sides (fig. 9, . If contact surfaces are perpendicular to effort operating on a stone stones will work only on compression. The first rule razrezki layings from this follows: beds of stones should be perpendicular to the forces operating on a laying, and stones in a laying should settle down horizontal numbers.
a Fig. 9. A stone laying :
And - dry without loading, - the same, under loading, in - on a solution, under loading
In everyone to a number stones stack so that there was no their shift. If lateral surfaces of stones are inclined to horizon (fig. 10) such stones in a laying form wedges 3, which stones 2 and 4 will move apart. In order to avoid it it is necessary, that for a plane, limitor one stones from others, were perpendicular to beds. At the same time if two lateral planes, limitor stones, are not perpendicular to external surfaces of walls, and two other lateral planes will not be perpendicular the first stones/, for example, having acute angles at an external surface, can drop out of a number and break integrity of a laying.
a Fig. 10. A laying cut by inclined planes of stones