SU1337475A1 - Method of thermal treatment of soil at post-like support - Google Patents

Abstract

The invention relates to the construction of a building and structures on weak drawers when soaking soils, in particular, to eliminating non-design deformations of columnar supports by reducing their friction of the soil under thermal effects. The invention is aimed at increasing the stability of the bearing by reducing friction of the drawdown soil on its surface. This is achieved by drilling the wells in two oppositely located groups — close to the support, three in each group at equal distances. The wells in each group are connected by slots. The injection of hot gases alternates with the injection of compressed air into the ground. Mathematical dependencies are given to determine the duration of the gas injection period. The wells, with free access to the support, are drilled evenly around the latter. To increase the efficiency, antifriction solution, a non-corrosive support reinforcement, is allowed. 3 hp f-ly, 2 ill., 1 tab. (L with her ip sd

Description

The invention relates to the construction of buildings and structures on weak subsiding soaking soils, in particular to the elimination of unprotected deformations of columnar supports by reducing their friction of the soil during thermal exposure.

The purpose of the invention is to increase the stability of the support due to the reduction of friction of the subsiding soil on its surface.

FIG. Figure 1 shows the support and the soil to be strengthened, the main equipment and means of technical control of the process, a longitudinal section; in fig. 2 support and borehole, cross section.

The method is carried out as follows.

First, around support 1, wells 2 are formed from two sides, three from each of them symmetrically close to support 1, at equal distances from each other. Then wells 2 are connected by slot 3 lie three wells together, seal the middle wells 4 at level 5, placed at a distance (O, 2-0.25) H - depth of the reinforced soil 6, lying to level 7. The heated gases are generated in the lower part 8 of medium wells 4 using elongated nozzles 9 connected to fuel tanks 10 and compressors 11 through valves 12. At the wellhead 4 nozzles 9 are fixed by diaphragms 13. Alternately burning the fuel mixtures in wells 4 and injecting compressed air lead through a period of time determined by the dependence of N.g „

g

n- (n + n)

(one)

where N is the depth of the subsidence of the soil, m;

H. - the sealing level of the lower part of the well from its bottom, m; P - soil porosity;

g, - well radius, m

Processing continues until at the outer edge 14 of the soil mass 6, spaced from support 15 of support 1 at a distance of about diameter of support 1, friction and adhesion forces are not reduced by the calculated value, qTo is determined by direct sampling through boreholes (not shown). The process is performed by a system of thermocouples 16 with instruments 17. The remaining wells 2 are sealed at the mouths.

4752

Placing wells 2 close to support 1 facilitates their drilling and relieves some of the stresses in the contact zone of the support — the ground. The formation of groups of three wells 2 on both sides ensures the stability of support 1 when drilling wells 2 ". The wells 2 are drilled on the sides not occupied by supra-bearing structures. If the support is free from all sides, then the wells 2 and the slots 3 are formed uniformly along the entire contour of the support 1.

For supports 1 bearing heavy loads, the reduction of friction forces during soil soaking is intensified after the last injection of compressed air, injection of 2 lubricating solutions into the wells, which do not have a corrective effect on the support fittings, for example, water with additives of used oils.

Example. At the reconstructed object, the building was erected on bored supports with a diameter of 1.2 m at a depth of 20 m in a subsidence type 11 loess-like soil, underlain by solid bedrock. With the rise of the groundwater level, the soil began to soak and the development of si.p friction, reducing the carrying capacity of the supports 1 and ryvshayus their additional non-design sediments.

Wells 2 in the amount of six pieces, three on each side of the support 1 were

c

drilled with the UGB-50 installation with a diameter of 0.1 m for the entire depth. Then the bore holes 2 simultaneously from two sides of the support 1 are cut by a slot 3 with a width of 2 cm, a device made on site that consists of three guide rods entering the wells and a cutting diaphragm between them, as well as rigidity diaphragms along the height of the device. Middle wells 4 were sealed at level 5 in 5 m from the bottom of the well 2, and the remaining at the mouths. Salt oil was burned, which was injected through nozzles 9 into the lower part of medium wells under a pressure of 0.1–0.2 MPa from Compressors 11 and the heated gases were generated there during the period defined by relation (1). According to the experiments, the magnitude of the velocity of the filter of gases was 0.08 m / s, the duration of the period of gas injection was assumed to be 1 hour at the porosity of the soil, 5. Friction and grip strengths

0

45

with the characteristics of the soil directly at the supports 1, which was checked by sampling of the soil and tested in the laboratory using standard methods.

The soil was treated around three pillars 1, two proposed and one known methods.

The results of the work are shown in the table.

Thus, the proposed method reduces the friction force around the supports by 2.78-4.76 times.

Claims (4)

Invention Formula 1, A method of thermally treating soil at a column support, including drilling wells, sealing them, generating a stream of hot gases in the lower part of the wells and periodically forcing hot gases and compressed air into the ground, characterized in that by ensuring the reduction of friction of the subsidence soil on its surface, the drilling of wells lead by two oppositely located groups closely to the support, three in each group at equal distances 0, 10 l 0.021 0.036 120 42 38 1 + 1 21 + 21 19 + 19 3860 2190 2430 Two entries at 62 and 58 hours after that, the wells are connected in each group by slits, and the injection of hot gases in each period is carried out over a period of time determined from the dependence . P (H + Ng) where H is the depth of the subsidence soil, m; Hp - the level of sealing the bottom of the well from its bottom, m; P - soil porosity; g - well radius, m 2 .., A method according to claim 1, characterized in that additional wells are drilled and additional slots are formed along the support contour. 3. Method pop. 1 and 2, characterized in that at the end of the last air injection, an antifriction solution is introduced into the wells, which does not corrode the support reinforcement and lubricate its surface. 4. A method according to claim 3, characterized in that a mixture of water with used oils is used as an anti-friction solution. /// IS 9 / " 4 -5 "Yig / .-f Editor A.Revin Compiled by A. Prkov Tehred M. Khodanich Proofreader V. But ha Order 4102/26 Circulation 606 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4