RU2058464C1 - Method for making foundation - Google Patents

Abstract

FIELD: civil engineering. SUBSTANCE: method includes driving a working though rocks along foundation route, placing explosives in lower portion of the working and firing the explosive followed by filling the working with concrete. The working is driven in the form of trench, explosive charges are fastened on inventorial H- beam between shelves on both sides of the wall along all beam length. The beam is placed in the bottom of the trench with free surface facing trench walls. Upon firing explosive, before filling the trench with concrete the beam is withdrawn out of the trench. EFFECT: high strength. 2 dwg

Description

 The invention relates to the construction of strip foundations for buildings and structures for various purposes, created by the method of "wall in soil", and can be used in the construction of low-rise buildings in dusty clay and subsidence soils made of cast concrete.

 When erecting foundations in an open foundation pit, the project of work execution envisages the following processes: excavating the pit, securing the walls of the pit, draining it, preparing the foundation, laying the foundations, and backfilling the sinuses with proper compaction. To ensure the normal conduct of work on the installation of foundations built in open pits, it is necessary to exclude the possibility of the collapse of their sides. The stability of the walls of the pit is ensured by giving them appropriate slopes or using special fasteners.

 The construction of foundations of cast concrete requires the use of formwork. The increasing volume of earthwork is associated with the need to introduce new progressive methods of building foundations into construction practice. One such method is a method conventionally referred to as a "wall in the ground." There is a method of constructing the foundations of the "wall in the ground", which consists in the construction of bearing walls of underground rooms by extracting deep and narrow trenches with vertical walls under a clay solution, followed by laying in a trench of monolithic or precast concrete or reinforced concrete. Clay solution protects the walls of the trenches from collapse, the depth of which can reach 35 m.

 When installing a monolithic concrete or reinforced concrete wall, the concrete mixture is laid in a trench by the method of a vertically moving pipe. When laying concrete, the clay solution is displaced and poured by gravity into the next grab trench, where soil is being disassembled, or the solution is pumped out for further use.

 When applying this method in subsiding soils, collapse of the vertical walls of the soil from the action of clay water is observed, which leads to an increase in concrete consumption. Fallen out soil settled at the bottom of the trench reduces the size of the trench, which requires additional funds and time to bring the trench to the design depth. All this leads to an increase in the cost of construction of the pit.

 In some cases, the deep foundation laid by the "wall in soil" method, which is arranged by drilling and filling secant wells with concrete, is obtained as follows. Under the protection of a solution of bentonite clay, two wells are first drilled in increments of one and a half diameters. Then they are filled with concrete mixture and after the concrete has begun to merge and after they have gained considerable strength, they drill a third well between them, followed by filling it with concrete mixture, etc. until the intersecting wells gradually form a wall of the required length and depth.

 With this method, a large amount of drilling work and a significant duration of the construction of the foundation are observed. In addition, the water of the clay solution, penetrating the soil, sharply reduces its strength properties and the stability of the walls of the well. This phenomenon is especially observed in soils classified as the second type by subsidence. This leads to an increase in the cost of work and a decrease in labor productivity.

 There is a method of securing a foundation pit with a collapsible wall, which includes dispersing wells along the contour of the pit during the formation of compacted soil around their zone and extracting the surrounding soil. Wells are stamped at a distance from one another, equal to the sum of the width of the well and twice the thickness of the compacted soil. This method increases the stability of the walls of the recess, but differs in very great complexity, the inability to control the quality of the seal and the need for further use of formwork for the construction of the foundation.

 A known method of creating a reinforced support array in the soil, which is the formation of wells, cutting holes from these wells in the soil using a liquid jet, filling the cracks as they are cut through with concrete, and introducing a reinforcing cage into it.

 The disadvantages of this method are: the need to have powerful additional water sources and sedimentation tanks for the formation of pulp, the complexity, and sometimes the inability to carry out work on the construction of foundations in the winter. In addition, when conducting work in planting soils, unwanted subsidence of the soil appears, which is the reason for the loss of stability of the walls of the trench. To strengthen the boards that have become unstable, additional fastening is required, which leads to concrete consumption and an increase in construction time. It is impossible to create a longitudinal cavity in soft soils to accommodate a monolithic foundation pillow, the width of which is greater than the width of the foundation wall, since uncompressed soil collapses.

 It is known that for the device of piles with broadening, extenders are used that form a circular cavity, but not a longitudinal one.

 Closest to the invention is a method of constructing a "wall in the ground", including drilling a well along a wall route, installing charges in part of the wells and then filling them with concrete. The maximum pairing of wells is obtained when explosives (EX) are exploded with the release of detonation products through unfilled wells. Before blasting the charges create pressure in the concrete mixture to a value equal to the pressure of the detonation products at the wellhead, and the release of detonation products is carried out upon reaching equal pressure values in all uncharged wells until the concrete mixture reaches the surface.

 With this method, the installation of special equipment increases the time and cost of work and it is impossible to create a longitudinal broadened cavity to accommodate a foundation slab whose width is greater than the width of the trench, which leads to an increase in material consumption and the volume of earthwork.

 These disadvantages are eliminated in the proposed method, where the mine workings are excavated in the form of a trench and placement of explosive charges in its lower part mounted on an inventory I-beam between the shelves on both sides of the wall along the entire length of the beam, the latter being placed at the bottom of the free trench the surface of the explosive charges towards the walls of the trench, and after the explosive is blown before filling the trench with concrete, the beam is removed.

 The essence of the method of construction of foundations in weak dusty clay soils is illustrated in Figs. 1 and 2, where Fig. 1 shows a trench with an I-beam with explosive charges placed in it; figure 2 shows a cavity filled with concrete and a trench.

 In the trench 1 there is an I-beam 2 with explosive charges 3 attached on both sides of the wall 4 of the I-beam 2 to its entire length. The side flanges 5 of the I-beam serve as guides of the explosion products towards the walls 6 of the trench 1 in order to obtain a cavity. The resulting cavity 7 and trench 1 are filled with concrete 8.

 To arrange the foundations according to the proposed method, according to the plan of their location, a trench is torn to the estimated depth of the foundation soles by an excavator or a barreling machine. On the beam, which is repeatedly used along its entire length, a solid charge is fixed with a tourniquet or detonating cord. As explosives, soda ammonite or cast trotyl are used. Blasting is used both electric and fire. After blasting, the resulting cavity and trench are filled with concrete using mechanisms, which are compacted with a vibrator.

 The effectiveness of the device of continuous monolithic foundation foundations by the “wall in soil” method with broadening of its sole in weak dusty clay and subsidence soils is achieved through the use of less expensive equipment, reduction of construction time, since the process of cavity formation and filling it with concrete are combined in time. Due to the lack of processes of tearing and backfilling of the sinuses of the foundations, the volume of earthwork is reduced. Due to compaction of the soil of the base, its bearing capacity increases, which reduces the width of the base of the foundation and, accordingly, the consumption of materials.

Claims (1)

 METHOD OF DEVICE FOR FOUNDATIONS, including driving mine workings along the foundation track, placing explosive charges in the lower part of the mine workings and blasting explosives with subsequent filling of the mine workings with concrete, characterized in that the mine workings are in the form of trenches, explosive charges are fixed on an I-beam between the shelves with both sides of the wall along the entire length of the beam, the latter is placed on the bottom of the trench with the free surface of explosive charges in the direction of the walls of the trench, and after the explosive is blown before filling the trench with concrete is removed from the trench.

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