Method to determine frost heave of soil during freezing of seasonally thawing layer

FIELD: construction.

SUBSTANCE: method to determine frost heave of soil during freezing of a seasonally thawing layer includes drilling of a well before start of its thawing, sampling of soil, measurement of depth of seasonal thawing ξ, definition of dry soil density in samples ρd,th. In addition wells are drilled after freezing of the seasonally thawing layer, on the samples they additionally define density of dry soil after freezing of the seasonally thawing layer ρd,f, and the heave value is determined in accordance with the given dependence.

EFFECT: reduced labour intensiveness of works, increased accuracy of determination of heaving value, provision of material intensity reduction.


The invention relates to the construction and production is intended for determining the frost heaving of the soil during freezing stenopodidea layer.

There is a method of determining the heaving of the soil, including the drilling of wells, installation of marker to a depth exceeding the depth of seasonal thawing of the soil, filling the sinus between the rapper and the borehole wall with a damp soil, the installation marks on the surface of the earth, monitoring vertical displacements of the brand relative to the frame during the entire period of freezing soil layer [1].

The disadvantages of this method is time consuming due to equipment frames, stamps and conducting long-term observations of swelling soil, as well as the significant cost of metal for the manufacture of frames.

The closest technical solution is the method of determining the frost heaving of the soil during freezing stenopodidea layer including drilling prior to freezing, soil sampling, measurement of the depth of seasonal thawing ξ, determination of the sample density of dry soil ρddensity of mineral particles ρs, soil moisture w, humidity unfrozen water ww(Tfh), humidity limits yield wLand rolling wp, minimum temperature zone pomerani the T fhestimated temperature at the ground surface, equal to the average temperature of the cooling medium during the freezing and calculate the magnitude of the rebound by the formula [2]

where ξ is the thickness of the soil layer before freezing; ρdthe density of the skeleton of the soil, g/cm3; ρwis water density, g/cm3; w - humidity thawed soil; ww(Tfh- the content (by mass) of unfrozen water in frozen soil at a temperature of 0.57 Tfh; Tfh- minimum temperature of the freezing zone, which stops the swelling; ζ=0 if w≤wu.fhand ζ=0,09 when w>wu.fh; wp- humidity limit rolling; T0f- the estimated temperature at the ground surface, equal to the average coolant temperature for the period of freezing.

The other parameters in the formula (1) are determined by the corresponding dependency graph.

The parameter Kbexpressing the vlagoprovodimosti thawed and frozen soils, in practical calculations can be accepted equal to

where wsat- full vaccum thawed soil.

The parameter ψ is determined from the graphs in figure 1 on the ratios of Tfh/T0ffor: (a) sandy loam, (b) loam, clay.

Correlative parameter ηwithexpressing the relationship between the temperature of the fittings and content of unfrozen water in the frozen zone (heave), and temperature Tfhare defined in table 1.

The first initial condition heave the humidity is determined by dependence

where 0,92 density of ice, g/cm3.

Table 1
Parameter values ηwith, kw(T) and temperature termination heave
Type of soilThe number of the plasticity of the soil, the proportion of edTemperature stop heaving, Tfh, °CThe value of the parameter ηwith
Sandy loam0,02<Ip≤0,07of-1.53,55
Sandy loam silt-2,05,00
Loam silta-2.55,00
Loam0,13<Ipwhat is 0,17 a-2.53,80
Loam silt-3,05,35

Critical humidity, which determines the second initial condition of rebound, found by the formula


where wL- the soil moisture content at the upper limit of plasticity (the border fluidity); Ip=wL-wp- the number of plasticity.

The value of wcrwhen ρs=2.7 g/cm3can be determined according to the schedule in figure 2 (dependence on humidity wcron the border of the fluidity of wLand plasticity Ip).

The disadvantage of this method is the high complexity of the work on the detection of a large number of characteristics of the physical properties and thermal state of the ground.

The purpose of the invention is to reduce the labor intensity, improve the accuracy of determining the amount of rebound, which can reduce the unnecessary expenses associated with the construction of buildings.

The objective is achieved by the fact that according to the method of determining the frost heaving of the soil has frozen the Institute stenopodidea layer, including the drilling of wells with samples before and after freezing Stonetalon layer, measure the depth of seasonal thawing ξ, the density of dry soil to the freezing Stonetalon layer ρd,thand after freezing ρd,fand I hope the swelling by the formula

The amount of rebound is the product of the thickness of the layer of soil to the freezing ξ on the ratio of the increment of the thickness of the layer of soil freezing hf-ξ and the thickness of the layer of thawed soil ξ

Express in the formula (7) hfand ξ through the respective volumes of the ground thawed in Vthand frozen VfStates and arbitrary cross-sectional area of the soil s

In the dependencies (8) the volume of thawed soil in Vthand frozen VfStates Express through the mass of dry soil mdand the density ρd,thand ρd,f

Substituting (8) and (9) in (7), we obtain a computational formula frost heaving frost susceptible soil (6):

An example of the method of determining the frost heaving of the soil during freezing stenopodidea layer

The method is tested on the patient "Tuymaada" Institute of the permafrost SB RAS.

Before the frost melted-through over the summer soil layer at the beginning of October, the special metal probe was determined by its thickness, formed ξ=1,65 m Then coring method was used to drill a well at the depth of the thawed-through layer. Every 30 cm of core cutting ring with a known volume (Vth) was selected samples of thawed soil was Packed them in accordance with the requirements of GOST 5180-2000, delivered in the soil laboratory, dried at 105°C in an oven, weighed the dried samples (md,th) and calculated the density of the skeleton thawed soil by the formula ρd,th=md,th/Vth.

The results of determination of the volume of the samples, the mass of dried soil and calculations of the density of the skeleton thawed soil are presented in the table below.

Table 2
The depth of sampling h, mThe mass of the dried soil sample md,thgThe volume of the cutting ring (wet soil) Vthcm3The density of the dry (skeletal) soil ρd,th, g/cm3

After freezing of the melted-through over the summer soil layer in the month of April was again well was drilled in 1 m from the first well of the same depth. Also every 30 cm core samples were taken of frozen soil to determine the density and moisture of soil, Packed, and delivered to the laboratory with negative temperature.

Samples for determination of moisture content of soil was weighed (mf,1), was dried in a drying Cabinet, the dried samples were again weighed (md,f) and expected moisture content of frozen soil by the formula wf=(mf,1-md,f)/md,f.

The weighings of the samples and determining the moisture content of the soil below the table.

Table 3
Depth selection
samples h, m
The sample mass
The mass of dried
sample md,fg
Douglas wf=(mf,1-md,f)/md,f

Samples for the determination of density of soil in accordance with GOST 5184-2000 processed to obtain a round shape, weighed in air (mf,2), grabbing a thin thread, dipped in kerosene and weighed in kerosene (mf) and was calculated density of frozen soil by the formula ρfkmf,2/(mf,2-mf), then find the density of the skeleton of frozen soil by the formula ρd,ff/(1+wf).

The weighings of samples of frozen soil on the air and kerosene with a density of pto=0,86 g/cm3and calculations of the density of frozen soil and the density of the skeleton of frozen soil below the table.

Table 4
The depth of sampling h, mThe sample mass in air mf,2gThe result of the weighting of samples in kerosene mf,KgThe density of the frozen ground pf, g/cm3The density of the skeleton frozen ground pd,f, g/cm3
0,9uniforms, 127.661,311,791,33

For comparison of results of determination of frost heaving of the soil of the proposed method at depths 0,3; 0,6; 0,9 and 1,2 m were established brand, vertical movement was determined by leveling relative to the fixed frame - metal pipes laid in the thickness of frozen ground to a depth of 9.0 m

Calculation data and results of the s definition of rebound method proposed according to the formula h fh=ξ(ρd,thd,f-1)and leveling listed in the following table.

Table 5
The depth interval, mThe power of the i-th soil layer ξimDensity
skeleton thawed
soil, g/cm3
the frozen skeleton
soil pd,f, g/cm3
The magnitude of rebound, cm
the proposed methodon leveling
i-th layer oftotal
0,9-1,2the 1.441,352,012,013,2

The maximum error in determining the amount of rebound of the proposed method is 18.8%, which is acceptable in terms of density changes of the skeleton of the soil in the horizontal plane.

Industrial applicability. The invention can be applied with success to determine heaving soils on the slopes of linear structures when calculating the depth of the support in the frozen ground.

Sources of information

1. Eagles V.O., Elgin B.B., Zheleznyak I.I. soil Frost heave in foundations of structures. - Novosibirsk: Izd-vo Nauka, 1987. - 136 C.

2. Fundamentals of Geocryology. Part 5. Engineering Geocryology. // edited AT Ershov. - M.: Izd-vo MGU, 1999. - 526 S.

The method of determining the frost heaving of the soil during freezing stenopodidea layer including drilling prior to freezing, soil sampling, measurement of the depth of seasonal thawing ξ, determination of the sample density of dry soil ρd,th, characterized in that it further drilling is performed after freezing stenopodidea layer on the samples additionally determine the density of dry soil after freezing stenopodidea slo is ρ d,fand the amount of rebound is determined by the formula:


Same patents:

FIELD: physics.

SUBSTANCE: method involves probing an underlying surface having test areas with a multichannel spectrometer mounted on a space vehicle to obtain images on each channel; calculating, through zonal ratios of signal amplitude values in channels, partial degradation indices, specifically percentage content of humus (H), salinity index (NSI) and moisture loss index (W); determining the integral degradation index D based on a multi-parameter regressive relationship of the type: D=(H0H)1,9(NSINSI0)0,5(W0W)0,3; recalculating image brightness pixel values in the scale of the calculated degradation index for each pixel; selecting outlines of resultant images thereof with the established gradations of the degree of degradation. (H0, NSI0, W0) are values of partial degradation indices for reference areas.

EFFECT: faster and more reliable determination of degree of degradation of soil cover.

5 dwg, 3 tbl

FIELD: mining.

SUBSTANCE: method includes installation of a device into a vertical position, and the device is a metal hollow cylinder enclosed into the body, along the inner and outer wall of which there is a cutting element welded in the form of a spiral, lowering of the cylinder to the specified depth during its rotation with cutting of a soil sample of cylindrical shape.

EFFECT: simplification and increased reliability in production of samples.

1 dwg

FIELD: agriculture.

SUBSTANCE: method includes device of cutting, measurement of parameters of soil layer and calculation. In the layer of peat ash the mass of diatomic algae shells is measured per one unit of plot area. The value of pyrogenic change of peat layer thickness is calculated by the following formula: H=α·m, where H - is the value of pyrogenic change of peat layer thickness, cm; α - is the coefficient, cm·m2/g; n - is mass of diatomic algae shells per unit of plot area, g/m2. The coefficient α is evaluate according to the formula: α=H1/m1, where H1 - is the peat layer thickness of the analogue plot, cm; and m1 - is the mass of diatomic algae shells per unit of analogue plot area, g/m2.

EFFECT: method enables calculate quickly and accurately the pyrogenic change value of peat layer thickness.

1 ex

FIELD: chemistry.

SUBSTANCE: method involves biotesting based on the number of organisms at optimum soil moisture. Soil toxicty is determined from the nitrogen-fixing activity legume bacteria which form tubercles on the root system of legume grasses in the 15-20 cm layer of the soil 2-3 weeks after spring aftergrowing and before the flowering period. Soil toxicity is determined from the inner colour of the nitrogen-fixing tubercles (pink or red); if more than 50% of the tubercles are coloured, the state of the soil is considered satisfactory, if 20-50% of the tubercles are coloured, the state of the soil is considered an environmental risk and if less than 20% of tubercles are coloured, the state of the soil is considered an environmental disaster.

EFFECT: method enables rapid and accurate evaluation of the degree of environmental pollution.

1 tbl, 6 ex

FIELD: oil and gas industry.

SUBSTANCE: in the device containing a tubular furnace equipped with a heater and a temperature control - the temperature programmer unit, located vertically and provided with cylindrical container with a soil sample, which is coaxially located in it. the inlet of the above furnace is connected to a pipeline with an activator of inert gas flow rate, and the outlet is connected through a quick-detachable connection to a hydrocarbon sensor represented with a flame ionisation detector, at the inlet of which a quartz capillary is installed, and the soil container is made in the form of a thin-wall shell from stainless steel with a porous bottom facing the tubular furnace inlet.

EFFECT: higher accuracy and informativity of analysis.

3 cl, 1 dwg

FIELD: agriculture.

SUBSTANCE: method includes geodetic measurements of the land plot area, three-dimensional measurement of the land plot, based on the measurement of the coordinate component of the resource parameters in different parts of this plot. Resource soil parameters of land plot are determined for each time period of operation taking into account the discrete disposal of part of the resources that were available at the beginning of the measurement period. In determining the resource parameters of the soil its biological activity is additionally measured on the stream of direct solar radiation reaching the horizontal surface of the soil.

EFFECT: method enables to improve the accuracy of measurement the resource parameters of the particular land plot.

1 tbl, 1 ex

FIELD: agriculture.

SUBSTANCE: method includes separation of air-dry aggregates. The separated aggregates are destroyed to the size smaller than 0.25 mm, moistened, dried, the self-collected structural units are separated from the structureless particles by circulating shaking (1.5 hours, 25 rpm), followed by sieving on a sieve of 0.25 mm and separation of water-resistant aggregates.

EFFECT: method enables to separate from the total soil mass the part which is the most active in terms of structure formation - the components capable to form spontaneously the aggregates after wetting-drying, enables to estimate the direction of aggregate formation processes in soil.

3 ex

FIELD: measurement equipment.

SUBSTANCE: for sampling in order to analyse soil a place is identified, as well as frequency, duration of soil sampling on sites according to a coordinate grid, indicating their numbers and coordinates. At the same time in each node of the coordinate grid or its part a site of soil sampling is laid with symmetrical shape with rows of soil sampling arranged symmetrically relative to borders of this site.

EFFECT: correlation of plant sampling for species diversity and soil sampling on an investigated site according to entire coordinate grid.

4 cl, 8 dwg, 6 tbl, 1 ex

FIELD: agriculture.

SUBSTANCE: method includes sampling of peat and vegetation growing on it. The samples of peat and vegetation are incinerated and the total content of Mn and Cr is determined in the ash. Biohpility of metals is calculated by the following formulae: AMn=Mnvegetation:Mnpeat and Acr=Crvegetation:Crpeat. The average degree of restoration of peat soil KRed is calculated by the formula: KRed=AMn:ACr.

EFFECT: method enables to determine quickly and accurately the average reductive-oxidative conditions in peat.

1 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: in the method, which involves collecting soil samples and determining content of gross forms of chemical elements on the investigated area and on the background territory and comparison thereof, the background territory used is buried soil under archaeological sites located on the investigated area.

EFFECT: simple analysis for determining soil contamination, shorter duration of sample preparation and analysis.

7 tbl

FIELD: measurement equipment.

SUBSTANCE: device for soil deformation measurement comprises a deformation-sensitive sensor optical cable, a measurement block connected with a cable, anchors connected to a cable and soil and is equipped with a system of cable protection against damage, including a safety fuse within each anchor, which actuates in case, when the force acting at the side of the anchor at the sensor cable exceeds the specified value.

EFFECT: provision of the possibility to limit a force transferred with an anchor to a sensor cable, in process of anchors displacement relative to each other, caused by soil movements, regardless of soil properties, which may be known unaccurately or change with time.

6 cl, 9 dwg

Sampler // 2484207

FIELD: construction.

SUBSTANCE: sampler comprises a sampling bushing made with the possibility to increase its cross section in process of sample withdrawal, a facility for sampling bushing insertion into a tested material. The sampling bushing is made from two chutes, longitudinal edges of which are equipped with alternating rectangular ledges and grooves, at the same time location of ledge section in one chute corresponds to location of second chute grooves, besides, loops are formed from the ledges of the chute edges, longitudinal axes of holes of which are parallel to the longitudinal axis of the chute and coaxial to longitudinal axes of the second chute loops. Chutes are coupled with each other by means of longitudinal edges. Through holes of the loops at each longitudinal edge of the chute there is a rod pulled, one end of which is equipped with a head, the section of which is more than the section of the hole, and the second end of the rod is equipped with threading, is pulled through holes of the slab made as capable of fixation on the vibrator and is fixed with a nut, at the same time the free end of the sampling bushing is equipped with a circular pad from magnetic material.

EFFECT: provision of integrity of an initial structure of a material sample during its withdrawal from a tested massif of a placer mine, provision of the possibility for material sampling from depth that is more than 2-3 m.

4 cl, 2 dwg

FIELD: construction.

SUBSTANCE: method is carried out by means of heading of containers, such as a cutting cylinder, onto a monolith. At the same time previously the soil is sampled. For this purpose a site is chosen, and in its centre a circular trench is dug with depth of not more than by 25 mm lower than the height of the cutting cylinder, belting the untouched soil, representing a truncated cone in shape, the diameter of the upper base of which is by 10…15 cm more than the inner diameter of the cutting cylinder, and the diameter of the lower base is more than the inner diameter of the cutting cylinder by 15…25 cm. From the soil left untouched the monolith is cut with the diameter of at least by 6 mm smaller than the inner diameter of the cutting cylinder and the height that is at least by 25 mm smaller than the cylinder height. At the same time the cylinder is periodically put on the monolith, using it as a template to monitor the diameter of the cut monolith. After cutting of the monolith and putting of the cutting cylinder on it, the cylinder is pushed into soil, until its upper layer levels with the monolith surface. In the space between the inner surface of the cutting cylinder and the outer surface of the monolith four Z-shaped supporting monolith-supporting plates are inserted with height equal to 3/4 of the cutting cylinder height. Evenly they are distributed along the cylinder perimetre and put on its upper edge. The slot between the inner surface of the cutting cylinder, the soil monolith and its supporting plates is filled with a molten waterproof material, having lower temperature of melting, for instance, a mineral wax. Afterwards the monolith is cut at the bottom at the lower edge of the cylinder, it is installed on the solid surface, packed and delivered to the area of filtration tests performance.

EFFECT: increased accuracy of soil filtration coefficient detection and accuracy of establishment of land reclamation system parameters, efficiency of using reclaimed soils, expanded zone of application of monoliths for detection of filtration coefficient.

3 dwg

FIELD: construction.

SUBSTANCE: method for laboratory determination of rheological characteristics of soils includes detection of deformation characteristics of undisturbed or disturbed soil under conditions of uniaxial compression without possibility of its side expansion in a compression device in the mode of stresses relaxation, and a compression curve is built by final values of stresses and their appropriate deformations of the sample as each stage is completed. For each of relaxation branches they build curves of deformation dependence on deformation speed. Then points are market on these curves with selected values of sample deformation speeds, their appropriate values of deformations are applied onto relaxation branches, and a bundle of curves is pulled through them, as corresponding to selected values of deformation speeds. Using these curves, they determine values of deformations corresponding to the selected value of the vertical load, and on the basis of this data they build curves of deformation dependence on time, by which they determine coefficients of filtration and secondary consolidation with available methods.

EFFECT: reduced terms and labour inputs for performance of laboratory tests for determination of rheological characteristics of soils, including detection of coefficients of filtration and secondary consolidation.

5 cl, 6 dwg

FIELD: instrument making.

SUBSTANCE: proposed device comprises cartridge for soil sample composed of rings and base with water feed chamber. Rings represent semi-rings fastened together to perform limited mutual displacement. Device uses tight chamber.

EFFECT: higher reliability of measurements.

1 dwg

FIELD: physics.

SUBSTANCE: device is a sleeve assembled from split rings which are provided with bands with given compliance with strain gauges, a tray, a porous insert for soaking the sample with water, a piston with a rod and freezing chamber mounted thereon. By rotating around the rod, the freezing chamber executes translational motion along the soil sample, providing the required speed of the freezing front.

EFFECT: high reliability of measurements.

1 dwg

FIELD: construction.

SUBSTANCE: invention relates to transport of hydrocarbons in oil and gas industry and may be used in operation of pipelines arranged in areas with possible landslip phenomena, to take timely measures for their protection against damage in case of soil displacement caused by disturbance of weight balance as a result of seasonal thawing, saturation of soil with water or other reasons. The device to record motion of soil in areas with possible landslip events along a pipeline installation route comprises a body, a metering lever, a hinged joint, a unit of movements count, a recording unit. The metering lever comprises a fixed anchor and N movable links, connected to each other with hinged joints, number of links depends on depth of unstable rocks that make up a landslip. The unit of movements count is installed into each movable link of the metering lever. The recording unit comprises a system of data collection and transfer for sending data online to a dispatcher's station.

EFFECT: invention provides for collection of information on a value, direction and speed of landslip mass motion at the entire depth of a movable soil layer online.

2 dwg

FIELD: construction.

SUBSTANCE: invention may be used to survey properties of frozen and non-frozen soils in field conditions when doing geological engineering, hydrogeological and geophysical survey to construct buildings and structures. A mobile laboratory for geological engineering survey in construction comprises monitoring and measurement equipment installed on a board with shock absorbers and fixed to laboratory tables with drawers, connected to an on-board PC, having a printer, chemical and analytical equipment and accessories, reagents, connection cables, laboratory glassware, consumables, a laboratory washer, a reservoir for water, work tables, an autonomous power unit in the form of a diesel engine with a power generator placed in an isolated compartment with a separate door, protected against noise, grounding, noise muffling, shock absorption, an air conditioner, a heating system. It is equipped with a block container capable of being installed on any vehicle. The block container is divided into three functional rooms, where laboratory equipment is installed. The monitoring and measurement equipment is equipped with tools for mechanical testing of soils both in frozen and non-frozen conditions arranged in one room, and equipment for physical survey of soils arranged in a different room. In the third auxiliary room in the form of the isolated compartment there is an autonomous power unit, which additionally holds a power board, a compressor and equipment for field testing of soils in the form of a screw stamp and drilling rods.

EFFECT: provision of mobile laboratory development with the possibility of installation on any vehicle provides for getting high operational results of laboratory tests, higher efficiency of a mobile laboratory.

20 cl, 2 dwg

FIELD: construction.

SUBSTANCE: method provides for taking sample blocks by a cylinder-sample block picker with the inner diameter D and the height H, with thickness of its wall h and angle of sharpening of its external cutting edge U°. In soils enriched with a rock material, sample blocks are taken with a cutting cylinder-sample block picker with D=180…220 mm, H=D, h=3…4 mm and U=40…45°. In soils with cracks, galleries of shrews, worms and root tubes of plants with D=180…220 mm, H=(0.8…1.0)D, h=1.5…3.0 mm and U=25…30°. In soils with less developed cracks and single root tubes of plants with D=130…180 mm, H=(0.8…1.0)D, h=1.5…3.0 mm and U=25…30°. In soils without cracks and other secondary pores, practically with no coarse soil with D=75…130 mm, H=(0.8…1.0)D, h=1.5…2.0 mm and U=25…30°. When developing a calculation method to determine a filtration ratio, with D=180…220 mm, H=(0.8…1.0)D, h=1.5…3.0 mm and U=25…30°. In all instances D does not exceed the capacity of a genetic horizon or a layer, from where a sample block is taken.

EFFECT: elimination of gross errors to determine a filtration ratio and water-physical properties of reclaimed soils and higher efficiency of mineral soils drainage.

FIELD: physics.

SUBSTANCE: method of measuring relative shear resistance of an elementary layer inside granular material moving together with a bogie under the action of a falling weight. The granular material is divided into two parts by a horizontal plate on the level of said elementary layer. The top part is put into a box which is connected by a thread to the recording device of a dynamometer, and the bottom part is moved relative the top part on a bogie. The shear resistance force is measured and continuously recorded on paper in a function of the shear path, and the weight of the empty box is considered as additional height of the granular material.

EFFECT: ensuring high accuracy of measuring shear resistance force of granular material without violating its structure and conditions in which it lies.

6 cl, 4 dwg

FIELD: engineering investigations in building, particularly devices for determining deformation and strength properties of ground in well.

SUBSTANCE: device comprises probe (working tip), control-rod, pipeline, communication line, loading jig and measuring station. Probe includes hollow cylindrical body with bottom and cap filled with working liquid, elastic shell sealed from body bottom and top. Formed in non-fixed elastic shell area are perforations. Piston with rod is installed in upper part of hollow body above working liquid. Rod passes through cap in sealed manner. Rod is connected with control rod so that piston may move in axial direction. Formed above piston is cavity connected to pipeline. Hollow body has bottom in which air-tight plug is installed. Measuring device is made as linear piston displacement transducer. Through orifices are formed in hollow body wall near body bottom. Arranged from body outside are vertical or inclined grooves aligned with through orifices by lower ends thereof. Air-tight plug is provided with adjustable rest for restricting piston stroke.

EFFECT: simplified structure of probe and measuring devices, increased operational reliability and improved validity of obtained data.

2 cl, 1 dwg