RU2692394C1 - Method of erecting piles in permafrost soils - Google Patents

Abstract

FIELD: construction.SUBSTANCE: invention relates to construction and can be used in construction of pile foundations on permafrost soils. Method of erecting piles in permafrost soil involves drilling a well, installing a pile in the face, filling the space between the pile and walls of the well and splitting part of the soil with a steam needle. Some part of the soil is thinned after the well is drilled in the bottomhole zone. Steam needle is installed in the well bottom and thaws the soil till the depth required for unobstructed installation of the pile, the steam needle is removed and the pile shaft is lowered into the stepped part of the ground with the help of the vibration loader. Space between pile and well walls is filled with hot clay solution with cement.EFFECT: technical result consists in improvement of bearing capacity of pile and its resistance to tilting, as well as in maintaining stability during sudden thawing.1 cl, 2 dwg

Description

The invention relates to the construction and can be used in the construction of pile foundations on permafrost soils.

There is a method of building a foundation with a negative ambient temperature on a permafrost base, which includes the development of the pit, the construction of the foundation body and the backfilling of the pit with soil with simultaneous water supply until the ground is completely saturated and backfilled with saturated soil at room temperature (USSR Authorization Certificate No. 487206, priority date 24.09.1973, publication date 10.10.1975, authors: Tsalyuk IG, et al., RU).

The disadvantages of this method are: limited scope due to the need to perform work only in winter at negative ambient temperatures, as well as heterogeneity of the composition of the backfill soil, which does not allow to obtain a monolith of frozen soil of high strength with the necessary adhesion force with the lateral surface of the basement body.

There is a method of erecting a pile in the permafrost soil, adopted as a prototype, including drilling a hole, installing a pile shaft in it, filling the space between the pile shaft and the well walls with frozen water-saturated ground pieces, then using the steam needle to thaw the upper part of the space to exceed the level formed during the thawing of ground mass over pieces of frozen soil (Patent RF №2039158 C1, priority date 01/06/1993, publication date 07/09/1995, author Khafizov P.M., RU, prototype).

The disadvantage of the prototype is the low resistance of the pile from the action of torque, loss of stability during sudden thawing.

The technical problem solved by the invention is to increase the bearing capacity of the pile, erected in permafrost soil, by ensuring the resistance of the pile to thawing torque.

To solve a technical problem, a method for erecting a pile in permafrost soil was proposed, including drilling a hole, installing a pile in the face, filling the space between the pile and the walls of the well and thawing a part of the soil with a steam needle. According to the invention, a new part of the soil is thawed out after drilling a well in the wellbore zone, the steam needle is installed in the well bottom and the ground is thawed to the depth necessary for unimpeded installation of the pile, and the melted part of the soil is removed using a vibrator. the pile shaft is lowered, and the space between the pile and the walls of the well is filled with a hot solution of clay and cement.

According to the invention, in the method, step drilling of a well is carried out with a decrease in the diameter of each subsequent cavity.

FIG. 1 schematically shows a three-stage well with a steam needle in the bottom of a well, a longitudinal section, a stage of thawing of a part of the soil; in fig. 2 shows a pile erected in a three-stage well, a longitudinal section, and the final stage.

The method of construction of piles in permafrost soil is as follows. On the surface of the soil 1, a well 2 is drilled with a diameter much larger than the pile diameter, 0.5-1 m deep, and the ratio of the diameter of the well and the pile is assumed to be, for example, 1: 0.4. Below the resulting cavity, a well 3 is drilled with a depth of 0.5-1 m from the original well with a ratio of well and pile diameters, for example, 1: 0.6. Next, drill the third well 4 with a depth of 0.5-1 m with a ratio of borehole and pile diameters, for example, 1: 0.7. A steam needle 5 is lowered into the bottom of the obtained three-stage well (Fig. 1). After the soil is heated to the depth necessary for the free installation of the pile, the pile driver 6 is installed in the thawed soil by the vibratory pile driver. Next, fill the cavity between the pile and the walls of the well with a hot solution of clay with cement 7 (Fig. 2). This increases the bearing capacity of the pile, its resistance to tilting, maintains stability during sudden thawing due to the increased diameter of the wellhead.

Thus, the technical result achieved when implementing the method of erecting a pile in permafrost soil is to increase the bearing capacity of the pile and its resistance to tilting, as well as to maintain stability during sudden thawing.

Claims (2)

1. The method of erecting a pile in the permafrost soil, including drilling a hole, installing a pile in the bottomhole, filling the space between the pile and the walls of the well and thawing a part of the soil with a steam needle, characterized in that the thawing of a part of the soil is carried out after drilling a hole in the bottomhole zone This steam needle is installed in the bottom hole and thawed soil to the required depth for free installation of the pile, remove the steam needle and into the thawed part of the soil using a lowering vibratory pile driver The pile shaft is filled, and the space between the pile and the borehole walls is filled with a hot clay mortar with cement. 2. The method of erection of a pile in the permafrost soil of claim 1, characterized in that they carry out stepwise drilling of the well with a decrease in the diameter of each subsequent cavity.

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