A kind of allpurpose model test pile
Technical field
The utility model relates to technical field of civil engineering, particularly relates to a kind of allpurpose model test pile.
Background technology
Along with the extensive use of pile foundation in building structure, at present the research of pile foundation bearing mechanism is more and more seemed important.Scale (model) test and on-the-spot full scale test are absolutely necessary for the research of the bearing mechanism of pile foundation.On-the-spot full scale test has certain advantage owing to considering actual field ambient conditions, but its experimentation cost is too high and test conditions is wayward; But model investigation has plurality of advantages, as controlled testing circumstance can be provided, the research of different tests parameter can be carried out in addition in more economical way.So become one of important method of research pile foundation bearing characters, more and more by the attention of scholars to the indoor scale (model) test research of stake correlation properties.
In the indoor scale (model) test of pile foundation, the preparation of Model Pile and soil around pile pressure measurement are extremely important links.Pile foundation test is divided into vertical load test, horizontal loading test and pullout tests substantially, and conventional test methods for these three kinds tests analogue formation stake respectively, thus makes workload increase.The Model Pile tradition method for measuring stress foil gauge monitor strain that normally utilizes pile body to be sticked in addition, then extrapolate pile body lateral stress, moment of flexure and end resistance etc. by pile strain, there is the problem that Model Pile makes complexity, projectional technique matching error and data processing error; Also have plenty of and lay stress measurement device in Model Pile surrounding soil, such as miniature earth pressure cell, but the method arrange measurement mechanism loaded down with trivial details and can disturbance pile peripheral earth stress field thus make to record result and do not conform to the actual conditions.Normally used Model Pile and pile body stress measurement mechanism manufacture and installation process complexity thereof, easily produce disturbance to former stress field, thus reduce the reliability obtaining data.In addition when simulating the test of stake by vertical load, horizontal loading, need the Model Pile that corresponds, complicated operation and expend larger.
Summary of the invention
The purpose of this utility model be in order to complicated for the stress method for measurement of existing model testing stake and with the problem such as true stress is not inconsistent, provide a kind of allpurpose model test pile that can use in multiple loading type model testing, this model testing stake not only can record the pile body lateral stress at end resistance and pile body diverse location place, compare traditional measurement mode very little to the field disturbance of stake circumferential stress, data measured is closing to reality more, and can vertical load test be carried out, horizontal loading test and pullout tests, decrease experiment work amount and improve test convenience.
The technical scheme that the utility model adopts is.
A kind of allpurpose model test pile, it comprises stake top, pile body, stake end, miniature earth pressure cell, vertical force sensor, described miniature earth pressure cell is embedded in pile body surrounding, and it is inner that described vertical force sensor is placed in stake end, and described stake end is positioned at model testing stake end.
Described model testing stake stake top comprises half ball pivot, walks wire connections, tension retainer ring; There is hemisphere half ball pivot one end, the other end with walk wire connections and be threaded, walking wire connections sidewall has the circular hole passed through for measure traverse line, and one end is provided with screwed hole in order to be hinged with hemisphere, and the other end is provided with screw thread and is connected with pile body; Tension Fixing shrink ring, can via being bolted to any position on pile body.
Model testing stake described pile body surrounding is provided with embedded hole, embedded hole depth 1mm less of stake internal diameter.Described miniature earth pressure cell is placed in the embedded hole of pile body, and measure traverse line pierces into pile body inside in pile lining aperture inside embedded hole.
It is inner that described vertical force sensor is positioned at stake end, and stake end is connected with force snesor through fixed head center hole by power transmission lever.Stake end detachably replaces with the stake end of different angles.Stay to establish between model testing stake stake end and pile body and be greater than 2mm gap, and in gap, lay sponge ring.Stake end detachably replaces with the stake end of different angles.
The embedded bore dia of model testing stake pile body is greater than miniature earth pressure cell diameter 1mm, fills transparent epoxy base resin in gap.
Compared with prior art, the beneficial effects of the utility model are:
1. at pile body diverse location place embedded miniature earth pressure cell amount in order to measure lateral earth pressure, vertical force sensor is laid to record end resistance in stake end inside, and measure traverse line is walked out from position, stake top via pile body inside, ensure that and measure pile body lateral earth pressure and end resistance under the prerequisite of the former pile-soil stress field of not disturbance, this Model Pile makes up the deficiency of conventional method, pile body lateral earth pressure distribution situation can be recorded comparatively intuitively, provide powerful support for for the bearing mechanism and mechanical property of analyzing pile foundation provide.
2. structure is simple, is convenient to installation and removal, can carries out vertical load, horizontal loading and pullout tests.The utility model is made up of 11 parts, and structure is simple, is easy to processing and installs.Meanwhile, half ball pivot, walk between wire connections, pile body, stake end to adopt thread connecting mode, easy for removal and installation.When carrying out the test of piles with different end angle, replaceable stake end pieces, and miscellaneous part still can continue to use.When carrying out stake end pullout tests, half ball pivot can be removed, replacing with draw ring, thus conveniently carry out pullout tests.Tension Fixing shrink ring moves up and down at pile body and by being bolted to any position, can carry out in the horizontal tension loading test of the Model Pile of differing heights pile body position.
3. certainty of measurement is high, and experimental data is reliable.When the ball pivot that model testing stake topmost is installed can reduce piling, load eccentricity is on the impact of Model Pile.Miniature earth pressure cell is embedded in model testing pile body surrounding and stays in the groove established, groove distributes from top to bottom from model testing stake, groove diameter is greater than miniature earth pressure cell diameter, then use transparent epoxy base resin by gap filling, the impact suffered by miniature earth pressure cell lateral force can be eliminated, improve the accuracy of miniature earth pressure cell survey data.Sponge is periphery and is located at stake end and pile body and stays between the gap of establishing, and not only can prevent the soil body from entering in gap, can not limit again the vertical displacement of the stake end be connected with power transmission lever, thus can ensure the accuracy of vertical force sensor measurement.
Accompanying drawing explanation
Fig. 1 is structural representation of the present utility model;
Fig. 2 is section of structure of the present utility model;
Fig. 3 is pile body sectional view of the present utility model;
Fig. 4 is stake roof construction sectional drawing of the present utility model;
Fig. 5 is stake end structure sectional drawing of the present utility model;
Fig. 6 is spherical hinge structure schematic diagram of the present utility model;
Fig. 7 is cabling connecting-piece structure schematic diagram of the present utility model;
Fig. 8 is tension retainer ring sectional drawing of the present utility model;
Fig. 9 is stake end structure sectional drawing of the present utility model.
In figure: 1 is half ball pivot, and 2 for walking wire connections, 3 is pile body, and 4 is tension retainer ring, and 5 is draw ring, 6 is miniature earth pressure cell, and 7 is vertical force sensor, and 8 is power transmission lever, and 9 is fixed head, 10 is stake end, and 11 is sponge ring, and 12 is measure traverse line, and 101 is hemisphere.
Detailed description of the invention
Below in conjunction with accompanying drawing, the utility model is further illustrated.
As shown in figs 1-9, the utility model by measuring soil pressure against piles at the embedded miniature earth pressure cell 6 of pile body diverse location, and uses the inner vertical force sensor 7 of the pile body be connected with stake end 10 to measure end resistance.Miniature earth pressure cell 6 diameter selected is 10mm, thickness 5mm, it is 11mm that pile body reserves embedded hole, is uniformly distributed along pile body vertical direction, each sectional uniform distributes four miniature earth pressure cells 6, and the gap between miniature earth pressure cell 6 and embedded hole uses transparent epoxy base resin filling.Tension retainer ring 4 can take off according to test requirements document or install, and also can adjust position on pile body and bolt is fixed.
Power transmission lever 8 has screw thread, and the screw thread mouth that stake holds 10 one end to be installed with coupling is connected with power transmission lever 8, and the two leaves the gap of 3mm after connecting, and in gap, is laid with sponge ring 11 enters pile body gap to prevent soil particle; The stake end 10 of the replaceable different angles of Model Pile, the stake end of such as 30 °, 45 °, 60 °, thus the Model Pile test that different angles stake end can be carried out.
Walk one end on wire connections 2 and have screw thread mouth, the other end has screw thread, and half ball pivot 1 one end is threaded and can be connected with the screw thread mouth walking wire connections 2, walks wire connections 2 and is connected with tapped pile body 3.Walk the circular hole that wire connections 2 bilateral symmetry leaves diameter 10mm, the measure traverse line 12 of miniature earth pressure cell 6 and vertical force sensor is walked out from circular hole by pile body inside.
When carrying out vertical load test, Model Pile is placed on native bed, acts on stake by test room's vertical loading device and push up on the hemisphere 101 of half ball pivot 1, Model Pile is pressed in native bed, then carries out Model Pile Vertical Static Loading Test.Half ball pivot 1 can prevent the Influence from Eccentric applying vertical load.
When carrying out horizontal loading test, draw ring 5 is arranged on tension retainer ring 4, then that tension Fixing shrink ring is fixing on pile body, to be connected with draw ring 5 by the steel strand of horizontal loading apparatus and to carry out horizontal loading test.
When carrying out pullout tests, half ball pivot 1 is taken off and replaces with draw ring, then use vertical loading device to be connected with draw ring and carry out pullout tests.