SU1694779A1 - Method for consolidating subsiding soil - Google Patents

Abstract

The invention relates to the construction, in particular, to the strengthening of subsiding soils during the preparation of bases for buildings and structures, and is aimed at improving the efficiency of soil hardening in depth with layers of different density and ensuring the erection of the foundations on the hardened soil on the foundation. the drilling time of the wells determines the height of the layers forming the array, and the mass of explosive charges is determined by the proposed mathematical dependence. Charges explosions are performed in liquid During the deposition of the well location grid, in the case of a building or structure erected on the foundations, the well positioning lines are aligned with the axis of the foundations, while the wells along the axis of the latter are drilled to the depth of the subsidence, at which the ground drawdown from its own weight does not exceed the ultimate deformations of it from the weight of the building, structure, the location of the wells is performed in steps determined by the proposed dependence. Mathematical dependences are given to determine the mass of charge and pitch of wells, 3 C. f-ly, 2 silt (L with

Description

The invention relates to the construction, in particular to the hardening of subsiding soils in the preparation of bases for buildings and structures.

The purpose of the invention is to increase the efficiency of hardening of the soil in depth with layers of different density and to ensure the erection of buildings and structures on foundations on the hardened soil.

Figure 1 shows a section of a reinforced soil array; Fig 2 - the location of the wells, the plan.

At the construction site, wells 1 are formed with a step of 2, determined from the dependence

oh oh

4 VI

VI

YU

and Cg Cg d.

0)

where Ki is a coefficient depending on the properties of the soil, is taken from experimental data for soils with a plasticity number of 0 03-0.1 - Ki 5,0, more than 0,1 - Ki 6,0,

Kr is a coefficient depending on the intensity of the charge, taken from experimental data at an intensity of 0.2 kg / n m. K2 - 3.0; 0.3 kg / pm - fc - 2.5; 0.4 kg / pm - K2 2.0; more than 0.5 kg / pm - Ka 1.8;

d is the initial diameter of the well.

The thickness of each geotechnical layer 3 is recorded; wells 1, located on the axis of the foundations 4, are made to the full depth of the subsidence layer 5, and located in the gaps 6 are made to a depth of 7, below which the ground sinks from its own weight do not exceed the maximum deformations of the foundation base. 8 of explosive 9, each layer 3 has its own linear mass of charge of explosive 9 determined from the dependence

G q

 one

Kihi

(2)

where q is the linear mass of charge for the soil layer with the lowest density of the soil in the dry state;

hi is the height of the 1st layer of soil;

KI is the coefficient of the 1st layer of soil, equal to the ratio of the density of the soil in the dry state of the 1st layer to the lowest density of the soil in the dry state over the depth of the compacting massif. The wells 1 are filled with liquid 10 and explosions of charges 8 of explosive 9 are carried out, cavities are obtained, the soil around which is evenly compacted. Then, in separate layers, starting from the soil that was poured into the wells, compacted the low compressible material supplied to the wells 1, for example, sand, slag, etc.

Example. The construction site is represented by subsidence soils with a capacity of 20 m, loams with a density of 1.49 g / cm3 are deposited from a depth of 9 m, and loess with a density of soil in a dry state of 1.39 g / cm is from the surface of the soil to 9 m.

The building in the plan had dimensions of 18 x 60 m with three spans of 6 m each. By drilling, wells were made with a diameter of 300 mm and a depth of 20 m along the axes of future foundations, and in the intervals of the well they drilled to a depth of 15 m, below which the ground subsidence the weight does not exceed the limit deformations of the base of the structure, which for production single-storey buildings with a full reinforced concrete frame is 8 cm.

The ground drawdown of the ground from its own weight from 15 to 20 m was determined by the well-known mathematical dependence

5 0 5

0

c

, “To

-Q 5g

Ssi 2) Јsii hi Ksis, i 1

where Јsii - relative subsidence of the 1st layer of soil;

hi is the thickness of the 1st layer;

n is the number of layers;

Ksii is the coefficient that, when determining the drawdown of the soil's own weight, Ksii 1 is taken.

Ss | 0,0148-5x1, 7.4 cm

The well positioning spacing a KrK2-d 5-2.95-0.30-3.3 m, for practical use, the value a was taken equal to 3 m.

Then, elongated explosive charges with a linear mass of charge to a depth of 9 m — 0.3 kg, and below — 0.35 kg, were placed in the formed wells, and below, 0.35 kg,

From a depth of 9 m, the wells were filled with a liquid component (thixotope substance) with a density of 1.1 g / cm3, and the upper part was filled with water. Then, an explosive charge was initiated. As a result of the charge explosions, cavities were formed with a diameter of 1.1-1.2 m, the soil around which was uniformly compacted. After that, slag (soil) was applied to the wells in separate layers with a height of 1.0 m, followed by clotting with a tamping mass of 3 tons. After the reinforced array was created, a distribution pillow was created.

The application of the proposed method allows to increase the uniformity of soil compaction, reduce the volume of reinforcing elements up to 30% with a corresponding saving of energy intensity and labor costs.

Claims (4)

Claim 1, A method of hardening an array of drawdown soil, including applying a grid of wells, drilling wells, placing elongated explosive charges in them, blasting the latter with the expansion of the cavity of the wells, compacting the soil spilled in the well and layer-by-layer filling of cavities with low-compressible material its compaction, characterized in that, in order to increase the effectiveness of soil reinforcement in depth with layers of different density, during the drilling of wells, e is the height of the layers composing the array, and the mass G of the charges of the explosive is taken to be equal to the value determined from the dependence G q Kihi where q is the linear mass of charge for the soil layer with the lowest density in the dry state; hi is the height of the 1st layer of soil; K | - coefficient of the 1st layer, equal to the ratio of the density of the soil in the dry state of the 1st layer to the lowest density of the soil in the dry state over the depth of the compacted array. 2. A method according to claim 1, wherein the explosions of charges are carried out in a liquid medium with different density densities. 3. The method according to claim 1, characterized in that, in order to ensure the erection of the buildings and structures on the foundations on the hardened soil on the foundations, during the application of the well positioning grid, their lines are aligned with the axes of the foundations, and drilling of the wells along the foundations lead to the depth of the subsidence, and the rest to the depth at which the ground drawdown from its own weight does not exceed its limiting deformations from the weight of the building, structure. 4. The method according to claim 1, about t l and h a and y and the fact that the location of the wells lead with step a, determined from the dependence a Ki is K2; d, where KI is the experimental coefficient characterizing the properties of the soil; K2 is the experimental coefficient characterizing the intensity of the explosion of a charge; d - the initial diameter of the wells.