RU1815308C - Method for construction of foundation - Google Patents

Abstract

Usage: the construction of foundations and structures in rammed pits. SUMMARY OF THE INVENTION: a ram is rammed with a rammer to a design depth. An explosive mass of 0.5–5 g is installed at the bottom of the pit. Hard soil material is poured on top onto a protrusion of 2.0–2.5 width or diameter of the rammer. A hollow template is mounted on a bed of hard soil material. The template follows the shape of a tamper and has a base in the base. The tamper is then discarded and the explosive charge is detonated. The magnitude of the impact of the tamper is taken equal to 0.02-0.08 of the magnitude of the explosion. Then the template is finished to the span mark of the sole of the foundation or to failure. After removing the template, the pit is filled with concrete. 2 s.p. 4-ill. ate with

Description

The invention relates to construction, in particular, to methods for erecting foundations in rammed pits in various soil conditions.

The purpose of the invention is to increase the bearing capacity of the foundation ..

Figure 1 shows a rammed foundation pit with an explosive charge mounted on its bottom and hard ground material dumped over it; Fig. 2 is the same, with a hollow template installed in the pit with a rampart in the lower part and a rammer at the moment of its impact on the rammer of the gauge and undermining the explosive charge; in Fig. 3, a template with a compaction zone and an enlarged fifth, completed by tampering to the design mark of the sole of the concrete block; Fig. 4 shows a finished foundation (concrete block) after removing the template and filling the pit with concrete.

The foundation construction method is carried out as follows.

Rammed trench pit 1 (figure 1) to the design depth with the formation along the contour of the pit of the compacted zone .2. Set at the bottom of the pit 1 charge of explosive 3 (for example, the most common ammonite No. 6 ZhV in construction practice) weighing 0.5-5 kg and pour hard soil material 4 (crushed stone, gravel, etc.) over it to a height no more than 2.0-2.5 width or diameter of the tamper in the lower section. Moreover, the minimum value of the mass of charge В В is determined based on the need to destroy the existing structure of compacted soil, and its maximum value is determined taking into account the minimum permissible depth of immersion of the explosive charge, mass and size of the tamper with a template, exclusion of softening of the soil, restrictions

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itismicity at the construction site and other factors, and the height of the fill from hard soil material is assigned with the most efficient compaction by tamping.

A metal hollow template 5 (Fig. 2), repeating the shape of the tamper and having a step 6 at the base, is installed in a rammed foundation pit for dumping from hard soil material. Then, the tamper 7 is discarded inside the template 5, a blow is made to the step 6, and the explosive charge is detonated. In this case, the magnitude of the impact action 8 of the rammer 7 when blasting the explosive charge is taken to be 0.02-0.08 the magnitude of the work of the explosion 9 (explosive effect) of the explosive charge, which also provides overlap of the shock and explosive effects within the layer equal to 1, 0-4.0 width or diameter of the tamper at the bottom. Moreover, to increase reliability and safety, an explosion locator is installed on the soil surface, if necessary, above the foundation pit.

Tamping template 5 (fig.Z) to the design level of the sole of the foundation or to failure and finally form the broadened heel 10 and compacted zone 2, of increased dimensions in plan and depth, which provides a significant (average 1.5-2 times) increase in bearing capacity of the base. If it is necessary to increase the bearing capacity of the foundation by increasing the size of the broadened heel made of hard soil material, the explosive charge is placed on the hard material rammed into the bottom of the foundation pit or additional volume is rammed into the bottom of the foundation pit after the template has been removed to failure.

The template is removed, the foundation pit is concreted and the finished foundation 11 is obtained (Fig. 4).

-Formula invention

Claims (2)

1. The method of construction of the foundation, including tamping the pit with a tamper, the formation of a broadened heel from hard ground material and the formation of a concrete block in the pit, characterized in that, in order to increase the bearing capacity of the foundation, the broadened heel is formed by detonating a charge of explosive weighing 0.5 - 5 kg s the formation of the cavity and filling the cavity with hard ground material, and the explosive charge and hard ground material are placed respectively on the bottom and bottom of the pit on a height of not more than 2.0 - 2.5 times the width or diameter of the rammer, and the explosive charge & substances are blown up when dropping the rammer, and before the charge is blown, a hollow template is installed on a hard soil material, repeating the shape of the rammer and having a ramp at the base, and after undermining the charge, the template is completed to the design level of the sole of the concrete block or to failure and the template is removed before the concrete block is formed, while the impact size of the tamper when the explosive charge is detonated is taken to be 0, 02 - 0,08 value of the explosion charge. 2. The method according to claim 1, characterized in that hard ground material is rammed into the foundation pit before the formation of the broadened heel. h. The method according to claim 1, characterized in that an explosion locator is installed above the foundation pit.