A kind of checkout gear of drift-sand bedding value and detection method
Technical field
The present invention relates to coefficient of subgrade reaction detection technique, be specifically related to a kind of checkout gear and detection method of drift-sand bedding value.
Background technology
For ensureing the safe operation of power line, pole and tower foundation is had to the design con-trol requirement of bearing capacity and displacement two aspect.And in the Its ultimate bearing capacity calculating of drift-sand ground transmission tower foundation, at present only using bearing capacity as design or checking computations parameter, and cannot displacement and bearing capacity be checked on both side, its key reason is the horizontal foundation coefficient lacking drift-sand ground, and the top priority recording horizontal foundation coefficient records foundation soil horizontal pressure force-displacement the Complete Curve.
Current, the test obtaining Foundation Soil Coefficient of Subgrade Reaction is generally Flat Dilatometer Test or plate.Flat Dilatometer Test at the trial the flat chisel gauge head be connected on feeler lever is pressed into desired depth in soil, then exert pressure, the circular steel membrane being positioned at flat chisel gauge head side is expanded to foundation soil, measures punching block and to expand the pressure of three specific positions, thus obtain multiple Geotechnical Parameter.Flat Dilatometer Test be applicable to weak soil, general cohesive soil, silt, loess and loose ~ in close sand.But the extreme displacement of Flat Dilatometer Test steel membrane only 1.10mm, to the requirement of pole and tower foundation control of horizontal displacement limit value at about 10mm in transmission line of electricity.Plate method records pressure force-displacement curve with the square pressure-bearing plate of certain specification, and represent coefficient of subgrade reaction with the slope of pressure force-displacement curve straightway.Although plate method can obtain examination soil from elastic stage to the pressure force-displacement curve of plastic failure overall process, but be only applicable to measure the vertical coefficient of subgrade reaction of foundation soil, and for the poor foundation soil of independence, as drift-sand, because test pit cannot be shaped, under not taking engineering to prop up gear measure situation, plate method is also inapplicable.
Therefore, how to design a kind of be applicable to drift-sand ground and can accurately obtain transmission tower under load action overall process pressure force-displacement curve, thus the checkout gear realized the control design case of pole and tower foundation bearing capacity and displacement two aspect or method, be this area problem demanding prompt solution.
Summary of the invention
In view of this, the checkout gear of a kind of drift-sand bedding value provided by the invention and detection method; This structure of the detecting device is simple and dismounting is convenient, achieves the measurement of the foundation soil horizontal loading-displacement the Complete Curve of the independence differences such as drift-sand, is applicable to various soil property simultaneously; The testing process of this detection method comprehensively, accurately and simply, make foundation soil consistent with actual load-bearing operating mode in the stress state of operating condition of test, improve validity and the accuracy of testing result, realize the control design case to pole and tower foundation bearing capacity and displacement two aspect, ensure that the safe operation of transmission line of electricity.
The object of the invention is to be achieved through the following technical solutions:
A checkout gear for drift-sand bedding value, described checkout gear comprises the casing that inside is provided with displacement detecting assembly;
Described casing comprises horizontal positioned and the outer case be flexibly connected and embedded case, and described outer case and embedded case are the rectangular box of one end open; The open side of described embedded case is closely inserted from the open side of described outer case and connects together with described outer case.
Preferably, described outer case is cuboid, and is pressure-bearing top board away from its open side and perpendicular to the plate of its length direction in described outer case; Be pressure-bearing baffle plate away from its open side and perpendicular to the plate of its length direction in described embedded case;
Described pressure-bearing baffle plate is identical with the shape of described pressure-bearing top board.
Preferably, described embedded case upper head plate be shorter in length than its bottom plate; Two side plates be clipped between described upper head plate and bottom plate are right-angled trapezium, and the right-angle side of described side plate is arranged on described pressure-bearing baffle plate;
Distance between described upper head plate and bottom plate is less than the height of described pressure-bearing baffle plate.
Preferably, described displacement detecting assembly comprises work dynamometer and the jack of coaxial connection, and the working end of described jack is provided with displacement transducer;
The fixed end of described jack is arranged on the center of described pressure-bearing baffle plate, and the working end of described jack is connected with one end of described operation detection instrument;
The other end of described operation detection instrument is arranged on the center of described pressure-bearing top board.
Preferably, the bottom bracing frame of the fixed end of described jack is fixed on described bottom plate.
A kind of drift-sand bedding value detection method, described detection method is detected by the drift-sand bedding value in drift-sand bedding value checkout gear region to be measured; Described checkout gear comprises horizontal positioned and the outer case be flexibly connected and embedded case, and the open side of described embedded case is closely inserted from the open side of described outer case;
Be provided with the work dynamometer and jack that are coaxially connected in the casing that described outer case and embedded case form, the working end of described jack is provided with displacement transducer;
Described method comprises the steps:
Step 1., according to the appearance and size of described checkout gear, is dug out and level can be put into the prospect pit of described checkout gear in the sand ground in region to be measured;
Described checkout gear level is put into described prospect pit by step 2., and debugs described checkout gear;
Step 3. successively applies horizontal loading step by step by checkout gear described in described jack pair, makes described embedded case and outer case generation relative displacement, and records the value of described horizontal load and the relative displacement applied each time;
The described horizontal load of step 4. according to record and the value of relative displacement, draw load-displacement curve;
Step 5. takes out described checkout gear, and increases the degree of depth of described prospect pit; Repeat step 2 to 4, until obtain the described load-displacement curve at the described prospect pit different depth place being greater than 2.
Preferably, described step 2 comprises:
Described checkout gear hangs in described prospect pit by 2-1., and is adjusted to horizontal positioned;
2-2. coarse sand or the original position soil body fill the hole parietal suture gap of the pressure-bearing baffle plate in described embedded case, the pressure-bearing top board in outer case and described prospect pit respectively; Wherein, described pressure-bearing baffle plate and pressure-bearing top board are respectively and are arranged on described checkout gear both sides and perpendicular to the rigid plate of described checkout gear length direction;
The horizontal stress of 2-3. pre-add 1kPa on described checkout gear, to eliminate the gap that wall cheated by embedded case and outer case and prospect pit.
Preferably, described step 3 comprises:
3-1. arranges the initial value of horizontal loading; If the soil property in described region to be measured is soft, then the initial value of described horizontal loading is 10 ~ 25kPa; If the soil property in described region to be measured is firmly close, then the initial value of described horizontal loading is 50 ~ 100kPa;
3-2. applies described horizontal loading by checkout gear described in described jack pair, makes described embedded case and outer case generation relative displacement;
3-3., after the indicating value of described work dynamometer and displacement transducer is stable, records the value of current described horizontal load and relative displacement thereof;
3-4. makes zero the indicating value of described work dynamometer and displacement transducer;
3-5. increases the value of described horizontal loading step by step, and returns step 3-2, until the number of times increased step by step reaches 8 ~ 10 times or described checkout gear occurs significantly need stopping situation;
Wherein, if the soil property in described region to be measured is soft, then the value of the described horizontal loading at every turn increased step by step is 10 ~ 25kPa; If the soil property in described region to be measured is firmly close, then the value of the described horizontal loading at every turn increased step by step is 50 ~ 100kPa.
Preferably, the described work dynamometer in described step 3-3 and the stable decision method of the indicating value of displacement transducer are: in continuous print 2 hours, if when the settling amount of described indicating value in per hour is all less than 0.1mm, then judge that described indicating value is relatively stable.
Preferably, the described obvious situation that need stop in described step 3-5 comprises:
There is obvious lateral extrusion or crackle in the soil a. around described pressure-bearing baffle plate or described pressure-bearing top board;
B. institute's displacement sensors indicating value sharply increases;
C., in 24 hours, described pressure-bearing baffle plate more than 0.12 times of the value of described relative displacement or described pressure-bearing top board obtain side length;
D. the value of current described relative displacement is more than or equal to the value 5 times of relative displacement described in previous stage.
As can be seen from above-mentioned technical scheme, the invention provides a kind of checkout gear and detection method of drift-sand bedding value, be provided with displacement detecting assembly in device comprises and horizontal positioned and be flexibly connected outer case and embedded case, the open side of embedded case is closely inserted from the open side of outer case; Method by successively applying horizontal loading step by step to checkout gear, record and draws the load-displacement curve of embedded case and outer case generation relative displacement, the load-displacement curve in the prospect pit of acquisition different depth.The checkout gear that the present invention proposes, its structure is simple and dismounting is convenient, achieves the measurement of the foundation soil horizontal loading-displacement the Complete Curve of the independence differences such as drift-sand, is applicable to various soil property simultaneously; The detection method that the present invention proposes, its testing process comprehensively, accurately and simply, make foundation soil consistent with actual load-bearing operating mode in the stress state of operating condition of test, improve validity and the accuracy of testing result, realize the control design case to pole and tower foundation bearing capacity and displacement two aspect, ensure that the safe operation of transmission line of electricity.
With immediate prior art ratio, technical scheme provided by the invention has following excellent effect:
1, in technical scheme provided by the invention, device by being provided with displacement detecting assembly in comprising and horizontal positioned and the outer case be flexibly connected and embedded case, the setting that the open side of embedded case is closely inserted from the open side of outer case; Make to the arrangement achieves self-balancing and without the need to counterweight, its structure is simple and dismounting is convenient, is applicable to the various soil conditions such as cohesive soil, silt, sand, gravelly soil, backfill or undisturbed soil simultaneously.
2, in technical scheme provided by the invention, device comprises work dynamometer and jack and the jack coaxially connected working end by moving detection components is provided with displacement transducer; Achieve the measurement of the foundation soil horizontal loading-displacement the Complete Curve of the independence differences such as drift-sand, improve validity and the accuracy of testing result, realize the control design case to pole and tower foundation bearing capacity and displacement two aspect, ensure that the safe operation of transmission line of electricity.
3, in technical scheme provided by the invention, method by successively applying horizontal loading step by step to checkout gear, record and draws the load-displacement curve of embedded case and outer case generation relative displacement, the load-displacement curve in the prospect pit of acquisition different depth; Make its testing process comprehensively, accurately and simply, make foundation soil consistent with actual load-bearing operating mode in the stress state of operating condition of test, improve validity and the accuracy of testing result, realize the control design case to pole and tower foundation bearing capacity and displacement two aspect, ensure that the safe operation of transmission line of electricity.
4, technical scheme provided by the invention, is widely used, and has significant Social benefit and economic benefit.
Accompanying drawing explanation
Fig. 1 is the elevation cross-sectional view of the checkout gear of a kind of drift-sand bedding value of the present invention;
Fig. 2 is the top plan view of the checkout gear of a kind of drift-sand bedding value of the present invention;
Fig. 3 is the internal construction schematic diagram after each parts of checkout gear of the present invention split;
Fig. 4 is the schematic flow sheet of the detection method of a kind of drift-sand bedding value of the present invention;
Fig. 5 is the schematic flow sheet of the step 2 in detection method of the present invention;
Fig. 6 is the schematic flow sheet of the step 3 in detection method of the present invention.
Wherein, 1-outer case, 101-pressure-bearing top board, the embedded case of 2-, 201-pressure-bearing baffle plate, 202-upper cover plate, 203-lower cover, 3-jack, 301-working end, 302-fixed end, 4-displacement transducer, 5-work dynamometer, 6-bracing frame.
Detailed description of the invention
Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on embodiments of the invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
As shown in Figures 1 to 3, the invention provides a kind of checkout gear of drift-sand bedding value, comprise the casing that inside is provided with displacement detecting assembly; Casing comprises horizontal positioned and the outer case 1 be flexibly connected and embedded case 2, and outer case 1 and embedded case 2 are the rectangular box of one end open; The open side of embedded case 2 is closely inserted from the open side of outer case 1 and connects together with outer case 1.
Outer case 1 is cuboid, and is pressure-bearing top board 101 away from its open side and perpendicular to the plate of its length direction in outer case 1; Be pressure-bearing baffle plate 201 away from its open side and perpendicular to the plate of its length direction in embedded case 2;
Pressure-bearing baffle plate 201 is identical with the shape of pressure-bearing top board 101.
The upper head plate 202 of embedded case 2 be shorter in length than its bottom plate 203; Two side plates be clipped between upper head plate 202 and bottom plate 203 are right-angled trapezium, and the right-angle side of side plate is arranged on the pressure-bearing baffle plate 201 in the casing of embedded case 2;
Distance between upper head plate 202 and bottom plate 203 is less than the height of pressure-bearing baffle plate 201.
Wherein, the upper head plate 202 of embedded case 2 is shorter than bottom plate 203 is constructional optimization, arranges reason and is: (1) bottom plate 203 plays the effect of fixing jack 3, therefore longer; (2) the acting as when embedded case 2, with outer case 1, relative displacement (being less than 10cm) occurs of upper head plate 202 and two side plates, in still can prevent the soil body landing from entering cavity that embedded case 2 and outer case 1 form; (3) shorter upper head plate 202 also reduces the material cost of instrument while alleviating instruments weight, and makes the Installation and Debugging of displacement detecting assembly more convenient.
Wherein, displacement detecting assembly comprises work dynamometer 5 and the jack 3 of coaxial connection, and the working end 301 of jack 3 is provided with displacement transducer 4;
The fixed end 302 of jack 3 is arranged on the center of the pressure-bearing baffle plate 201 in casing, and the working end 301 of jack 3 is connected with one end of operation detection instrument;
The other end of operation detection instrument is arranged on the center of the pressure-bearing top board 101 in casing.
The bottom bracing frame 6 of the fixed end 302 of jack 3 is fixed on the bottom plate 203 of the embedded case 2 being positioned at casing.
The invention provides a kind of drift-sand bedding value detection method, detected by the drift-sand bedding value in drift-sand bedding value checkout gear region to be measured; Checkout gear comprises horizontal positioned and the outer case 1 be flexibly connected and embedded case 2, and the open side of embedded case 2 is closely inserted from the open side of outer case 1;
Be provided with the work dynamometer 5 and jack 3 that are coaxially connected in the casing that outer case 1 and embedded case 2 form, the working end 301 of jack 3 is provided with displacement transducer 4;
As shown in Figure 4, method comprises the steps:
Step 1., according to the appearance and size of checkout gear, is dug out and level can be put into the prospect pit of checkout gear in the sand ground in region to be measured;
Checkout gear level is put into prospect pit by step 2., and debugging detection device;
Step 3. successively applies horizontal loading step by step by jack 3 pairs of checkout gears, makes embedded case 2, with outer case 1, relative displacement occur, and records the value of horizontal load and the relative displacement applied each time;
The horizontal load of step 4. according to record and the value of relative displacement, draw load-displacement curve, i.e. F-S curve;
Step 5. takes out checkout gear, and increases the degree of depth of prospect pit; Repeat step 2 to 4, until obtain the load-displacement curve at the prospect pit different depth place being greater than 2.
As shown in Figure 5, step 2 comprises:
Checkout gear hangs in prospect pit by 2-1., and is adjusted to horizontal positioned;
2-2. coarse sand or the original position soil body fill the hole parietal suture gap of pressure-bearing baffle plate 201 in embedded case 2, pressure-bearing top board 101 in outer case 1 and prospect pit respectively; Wherein, pressure-bearing baffle plate 201 and pressure-bearing top board 101 are respectively and are arranged on checkout gear both sides and perpendicular to the rigid plate of checkout gear length direction;
The horizontal stress of a 2-3. pre-add 1kPa on detection means, to eliminate embedded case 2 and outer case 1 cheats the gap of wall with prospect pit.
As shown in Figure 6, step 3 comprises:
3-1. arranges the initial value of horizontal loading; If the soil property in region to be measured is soft, then the initial value of horizontal loading is 10 ~ 25kPa; If the soil property in region to be measured is firmly close, then the initial value of horizontal loading is 50 ~ 100kPa;
3-2. applies horizontal loading by jack 3 pairs of checkout gears, makes embedded case 2, with outer case 1, relative displacement occur;
3-3. after the indicating value of work dynamometer 5 and displacement transducer 4 is stable, the value of record present level load and relative displacement thereof;
3-4. makes zero the indicating value of work dynamometer 5 and displacement transducer 4, and its method of operating is " zero " button on click work dynamometer 5 and the corresponding display of displacement transducer 4, and the indicating value making dynamometer and displacement transducer 4 makes zero;
3-5. increases the value of horizontal loading step by step, and returns step 3-2, until the number of times increased step by step reaches 8 ~ 10 times or checkout gear occurs significantly need stopping situation;
Wherein, if the soil property in region to be measured is soft, then the value of the horizontal loading at every turn increased step by step is 10 ~ 25kPa; If the soil property in region to be measured is firmly close, then the value of the horizontal loading at every turn increased step by step is 50 ~ 100kPa.
Work dynamometer 5 in step 3-3 and the stable decision method of the indicating value of displacement transducer 4 are for adopting the relatively stable method of displacement, namely after every grade of loading, by interval 10,10,10,15,15min, survey the indicating value reading a displacement transducer 44 every half an hour: in continuous print 2 hours later, if when the settling amount of indicating value in per hour is all less than 0.1mm, then judge that indicating value is relatively stable.
The obvious situation that need stop in step 3-5 comprises:
There is obvious lateral extrusion or crackle in the soil a. around pressure-bearing baffle plate 201 or pressure-bearing top board 101;
B. displacement transducer 4 indicating value sharply increases;
C. in 24 hours, pressure-bearing baffle plate 201 more than 0.12 times of the value of relative displacement or pressure-bearing top board 101 side length;
D. the value of present relative displacement is more than or equal to the value 5 times of previous stage relative displacement.
Wherein, the horizontal foundation modulus K of any depth
hcalculated by following formula:
In formula,
for the slope of F-S curve straightway, when in F-S curve without straightway time, F gets the half of critical edge pressure, and S is the horizontal movement in response to this F value;
A is the contact area of embedded case 2 or outer case 1 and the prospect pit borehole wall, i.e. the area of pressure-bearing top board 101 or pressure-bearing baffle plate 201;
K
h---horizontal foundation modulus.
Above embodiment is only in order to illustrate that technical scheme of the present invention is not intended to limit; although with reference to above-described embodiment to invention has been detailed description; those of ordinary skill in the field still can modify to the specific embodiment of the present invention or equivalent replacement; and these do not depart from any amendment of spirit and scope of the invention or equivalent replacement, it is all being applied within the claims of the present invention awaited the reply.