CN101424087A - Insulation and collecting well - Google Patents

Abstract

The invention relates to a heat preservation collecting well, which consists of a turf cover layer, an earth fill layer, heat preservation layers, block stone layers, a water permeable geotextile, and a water outlet. The bottom part of the well, a water outlet end face of a well mouth or the lateral surface of the well wall are provided with the heat preservation layers; two sides or one lateral surface of the well wall is provided with the water permeable geotextile; the block stone layers are stacked in the well; the top part of the well is the earth fill layer; the turf cover layer is above the earth fill layer; and the water outlet is connected with an underground drainage pipe. The heat preservation collecting well uses the water permeable geotextile to replace an inverted filter layer consisting of gravels and block stones of the prior measure to greatly improve construction speed, and uses an extrusion molding polyethylene heat preservation plate to produce double effects of water isolation and heat preservation so that the heat loss in the collecting well is little. The heat preservation collecting well has simple structure, easy and quick construction, and perfect heat preservation effect, is advantageous for drainage, reduces engineering frozen injuries caused by unsmooth drainage in winter, and can be widely applied to underground water collecting and draining systems for projects of highway, railway and the like in cold areas.

Description

Insulation and collecting well

Technical field

The present invention relates to a kind of cold district underground water collection structure.Be fit to that cold district undergroundly catchments, drainage system uses.

Background technology

China has most of area to be in cold district.The highway construction of Han Qu, mine engineering all relate to phreatic collection and drainage.Tradition is collected phreatic mode and is adopted the seepage well that catchments, catchments and ooze pond collection underground water, then by hidden pipe, blind drainage.Because cold district winter climate cold, frozen, obstruction that water collecting structure, hidden pipe, french drain are easy to causes whole water collecting and drainage system to lose efficacy, and causes damage to engineering; Its water collecting structure mainly reaches insulation by increasing soil thickness, and this method construction is slow, weak effect and be unfavorable for environmental protection.Modal is exactly the highway of Han Qu, the generation of railway salivary flow ice evil, brings serious hidden danger to traffic safety, has also caused enormous economic loss simultaneously.The generation of salivary flow ice is because discharge pipe line stops up, water from some the local exposure of roadbed top, freeze, spread to roadbed on the face of land, culvert blocks up, the ice dissolution in spring, because drainage channel is iced obstruction, cause melt water to wash away road, these bring very big threat to the stable of road and ancillary structure with traffic safety.In addition, China northeast, the many frontier defense roads in northwest suffer the harm of salivary flow ice throughout the year, and highway is blocked, and the conveying of army's desired substance is subjected to very big influence.

Improve the water temperature in the collecting well, can prevent effectively that discharge pipe line from freezing.Adopt electrically heated mode in the Muscovite railway salivary flow ice control, the application of this method is subjected to the restriction of many conditions, is not suitable for the numerous Han Qu of China and uses.The existing traditional seepage well that uses, ooze the pond, adopt clay to do water barrier, coarse sand, rubble and do loaded filter, complex structure, difficulty of construction is big, and another most important reason is exactly that heat insulation effect is undesirable, has by a relatively large margin in the catchment water temperature and reduces, and is unfavorable for draining.Therefore, it is significant to the highway, the railway salivary flow ice evil problem that solve Han Qu to research and develop a kind of novel and effective insulation and collecting well.

Summary of the invention

For overcome the existing seepage well of Han Qu, ooze that the pond heat insulation effect is undesirable, complex structure, defective that difficulty of construction is big, the invention provides a kind of insulation and collecting well.This collecting well adopts heat insulating material XPS plate to be incubated processing, as loaded filter, stacks piece stone with permeable geotextiles in the well, carries out turf simultaneously at the collecting well top and covers, and strengthens heat insulation effect.Can improve speed of application thus greatly and improve water temperature in the collecting well, reduce the possibility that discharge pipe line freezes, reduce the loss that cold district engineering is brought because of drainage problem.

The technical solution adopted for the present invention to solve the technical problems is:

A kind of insulation and collecting well is made of herbaceous soil covering, fill stratum, insulation layer, block stone layer, permeable geotextiles, delivery port.Be provided with insulation layer in borehole wall bottom, well head water outlet end face or the borehole wall one side, a borehole wall both sides or a side are provided with permeable geotextiles, stack block stone layer in the well, and the top of well is a fill stratum, herbaceous soil covering is arranged on the fill stratum, and delivery port and subsoil drain link in the well.

Above-mentioned insulation layer adopts the extruded polyethylene plate, and thickness range is 5～20cm, coefficient of thermal conductivity 0.028W/mK; Compressive strength is greater than 0.3Mpa, and the volume water absorption rate is less than 1%.

Above-mentioned permeable geotextiles transmission coefficient is not less than 2cm/s.

Above-mentioned block stone layer particle size range is 10～25cm.

Above-mentioned backfill thickness is 20～50cm.

The operating principle of insulation and collecting well is: the underground water in the aquifer enters in the collecting well by permeable geotextiles, drains by drainage outlet then, and outfall and subsoil drain join.The collecting well bottom, the good extrusion molding foam heat insulating material of heat insulation effect XPS plate is all arranged at side and top, and this has significantly reduced the loss of hydro-thermal amount in the collecting well.

Because there is the process of freezing and melting in soil around the collecting well.Calorifics problem of the present invention is the thermal field problem of band phase transformation, adopts the numerical experimentation method can carry out the checking of heat insulation effect.The thermal balance control differential equation is:

Just freezing the district,

$C_f\frac{{\∂T}_f}{\∂t}=\frac{\∂}{\text{\∂x}}\left({\mathrm{\λ}}_f\frac{{\∂T}_f}{\∂x}\right)+\frac{\∂}{\∂y}\left({\mathrm{\λ}}_f\frac{{\∂T}_f}{\∂y}\right)+\frac{\∂}{\∂z}\left({\mathrm{\λ}}_f\frac{{\∂T}_f}{\∂z}\right)---\left(1\right)$

In melting,

$C_u\frac{{\∂T}_u}{\∂t}=\frac{\∂}{\text{\∂x}}\left({\mathrm{\λ}}_u\frac{{\∂T}_u}{\∂x}\right)+\frac{\∂}{\∂y}\left({\mathrm{\λ}}_u\frac{{\∂T}_u}{\∂y}\right)+\frac{\∂}{\∂z}\left({\mathrm{\λ}}_u\frac{{\∂T}_u}{\∂z}\right)---\left(2\right)$

In the formula: symbol f, u represent to freeze, melt state, T respectively _f, C _f, λ _fBe respectively the temperature, volume specific heat and the coefficient of thermal conductivity that just freeze medium in the district, band " u " person is the respective physical amount in the tabetisol.

Handle the phase transformation problem with enthalpy, can be write formula (1), (2) as unified form:

$C\frac{\∂T}{\∂t}=\frac{\∂}{\text{\∂x}}\left(\mathrm{\λ}\frac{\∂T}{\∂x}\right)+\frac{\∂}{\∂y}\left(\mathrm{\λ}\frac{\∂T}{\∂y}\right)+\frac{\∂}{\∂z}\left(\mathrm{\λ}\frac{\∂T}{\∂z}\right)---\left(3\right)$

Adopt above governing equation, by Finite Element Method, the present invention is incubated water collecting structure carries out numerical experimentation, the result shows: the fluctuating temperature that enters whole winter in the collecting well is very little, and thermal loss is very little.In addition, the structure 2004 beginnings of the present invention salivary flow ice of Daxing'an Mountainrange forest highway northeastward are applied in preventing and treating, the field observation data show that the water temperature in the insulation and collecting well is higher 4～5 ℃ than the water temperature in traditional collecting well, above evidence explanation heat insulation effect ideal of the present invention.

The beneficial effect of advantage of the present invention and generation is:

1, the present invention adopts the extruded polyethylene plate, has played the double effects of water proof, insulation; Secondly the extruded polyethylene plate greatly reduces top soil thickness (formula 4), and the heat insulation effect of 20cm thickness extruded polyethylene plate is equivalent to the heat insulation effect of local 2～5m thickness soil layer; The top is provided with herbaceous soil covering simultaneously, has kept original geomorphologic landscape, is beneficial to environmental protection.

2, replace the rubble of traditional measures, the loaded filter that piece stone is formed with permeable geotextiles, improved speed of application greatly;

3, because the improvement of the use of new material and structure has improved the water temperature in the collecting well, reduce the possibility that the underdrainage pipeline freezes, reduced the destruction that cold district engineering causes because of drainage problem.

Heat insulating material reduces the maximum ga(u)ge value of banketing and can be calculated as follows:

In the formula: H is for reducing the maximum ga(u)ge of soil layer; λ _BanketThe coefficient of thermal conductivity that expression is banketed; λ _{Heat insulating material}Be the heat insulating material coefficient of thermal conductivity; h _{Heat insulating material}Be heat insulating material thickness.

Description of drawings

Fig. 1 insulation and collecting well longitudinal plan.

Fig. 2 is A-A ' profile of Fig. 1.

The specific embodiment

For understanding the present invention better, can be further specified by following examples, but be not limitation of the invention.

As shown in Figure 1, a kind of insulation and collecting well is made of herbaceous soil covering 1, fill stratum 2, insulation layer 3, block stone layer 4, permeable geotextiles 5, delivery port 7.Be provided with insulation layer 3 in borehole wall bottom, well head water outlet end face or the borehole wall one side, a borehole wall both sides or a side are provided with permeable geotextiles 5, stack block stone layer 4 in the well, and the top of well is a fill stratum 2, herbaceous soil covering 1 is arranged on the fill stratum 2, and delivery port 7 links with subsoil drain.

The insulation and collecting well that adopts with Rameau highway K81+300 place, Daxing'an Mountainrange is an example.Geographical coordinate: N50 ° 47.759 ', E120 ° 03.758 '.Height above sea level 774m belongs to the high latitude cold district.

Work progress is: open the face of land, the position turf that catchments earlier, recover face of land view in order to the completion back; Dig a dark 205cm in the position of catchmenting, long 200cm, the well of wide 200cm cuboid, bonding between plate at the extruded polyethylene warming plate of bottom, well head water outlet end face and a side laying 15cm thickness with cementing agent, form insulation layer 3; The hole 7 that apart from bottom 10cm height and position a diameter 20cm is set on the water outlet end face is connected with subsoil drain, and the horizontal level in hole is positioned at the middle part of length direction (the section direction vertical with gutter is length direction); Be the block stone layer 4 of 20cm stacking average grain diameter then near extruded polyethylene warming plate position, further fixedly insulation layer 3, coming the water surface to lay permeable geotextiles 5 then as loaded filter, continue to stack piece stone afterwards, form block stone layer 4 when reaching the 150cm height, the stop piece clitter is put, and repaves to cover the thick extruded polyethylene warming plate of 20cm; After the 40cm that bankets formation fill stratum 2 suitably rolls, the former turf of opening is covered the top of collecting well.Underground water 6 infiltrates in the well by permeable geotextiles 5, discharges from outlet pipe 7.

Extruded polyethylene warming plate coefficient of thermal conductivity 0.028W/mK, intensity 400kPa, (the water vapour moisture permeable coefficient is less than 2ng (Pa.m.s), and corrosion-resistant, heat-insulating property is stable less than 1% for the volume water absorption rate.The XPS plate of top 20cm thickness is equivalent to the soil layer of local 3m thickness.The vertical transmission coefficient 3cm/s of geotextiles, its mass area ratio 450g/m ², tensile strength 10kN/m.

Present embodiment is constructed in the autumn in 2004 and finished, and is through the practical proof in 3 winters, satisfactory for result.This water collecting structure since around the insulation effect recovered of the application of heat insulating material and top vegetation ecological, water temperature in winter obtains bigger raising in the collecting well, improves about 4～5 ℃ of water temperature.

Claims (5)

1, a kind of insulation and collecting well, constitute by herbaceous soil covering (1), fill stratum (2), insulation layer (3), block stone layer (4), permeable geotextiles (5), delivery port (7), it is characterized in that: be provided with insulation layer (3) in borehole wall bottom, well head water outlet end face or the borehole wall one side, a borehole wall both sides or a side are provided with permeable geotextiles (5), stack block stone layer (4) in the well, the top of well is fill stratum (2), herbaceous soil covering (1) is arranged on the fill stratum (2), and delivery port (7) links with subsoil drain in the well.

2, insulation and collecting well according to claim 1 is characterized in that: insulation layer (3) adopts the extruded polyethylene plate, and thickness range is 5～20cm, coefficient of thermal conductivity 0.028W/mK; Compressive strength is greater than 0.3Mpa, and the volume water absorption rate is less than 1%.

3, insulation and collecting well according to claim 1 is characterized in that: permeable geotextiles (5) transmission coefficient is not less than 2cm/s.

4, insulation and collecting well according to claim 1 is characterized in that: block stone layer (4) particle diameter is 10～25cm.

5, insulation and collecting well according to claim 1 is characterized in that: fill stratum (2) thickness is 20～50cm.

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