Buttress foundation structure for large-tonnage pile foundation static load test

Abstract

The utility model discloses a buttress foundation structure for a large-tonnage pile foundation static load test, which belongs to the technical field of buttress structures for static load tests, and comprises a plurality of reinforced concrete cast-in-place piles and steel columns with the corresponding number, and the lower ends of the steel columns are pre-embedded in the reinforced concrete cast-in-place piles. The lower ends of the reinforced concrete cast-in-place piles downwards penetrate through the soft soil layer and extend to be embedded into the pebble bed; the multiple reinforced concrete cast-in-place piles are transversely and longitudinally arranged at intervals in an array mode, transversely adjacent steel columns are connected through long steel beams, longitudinally adjacent steel columns are connected through short steel beams, the top ends of the reinforced concrete cast-in-place piles, the top faces of the long steel beams and the top faces of the short steel beams are equal in height and flush, and carrying plates are laid on the tops. According to the utility model, the load of static loading and stacking can be effectively transmitted to a bearing soil layer, and most structures are steel structures, so that one pile foundation can be repeatedly used in a dismounting and remounting manner after being detected, and the cost is greatly reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of buttress structures for static load tests, in particular to a buttress foundation structure for static load tests of large-tonnage pile foundations. Background Art

[0002] In construction projects, static load test is the most direct, reliable and direct test method to determine the bearing capacity of pile foundation and foundation. Therefore, many current specifications use it as an important basis for engineering design and construction acceptance. It is a test method that simulates the working conditions of building foundations.

[0003] The weighted platform loading method is a commonly used large-tonnage static load test method. The test equipment required is as follows: Figure 4 As shown, it mainly includes a pile foundation a to be tested, a jack b is arranged on the top of the pile foundation, the top of the jack b is abutted against a cap plate c, the top of the cap plate c is used to prevent the heavy object d from controlling the applied load, and for the purpose of structural balance, piers e are usually arranged on both sides of the bottom of the cap plate c, and the lower ends of the piers e are usually connected to the ground or underground foundation.

[0004] The test method of the weight platform heap loading method is to use a manual hydraulic jack b for loading. The load value and settlement are measured manually with an oil pressure gauge and a dial gauge respectively, and the data processing is also completed manually. The RSM static load tester uses advanced wireless data acquisition technology to control the hydraulic system to automatically load, supplement, maintain load, automatically determine stability, automatically save data, and automatically draw QS, S-1gQ, S-1gt curves.

[0005] In actual engineering applications, if the foundation at the lower end of pier e is not stable enough, especially when pile foundation a is a large-tonnage pile foundation (that is, the required test load exceeds 20,000 kN) and the foundation at the lower end of pier e is a soft soil foundation, it is easy to cause serious subsidence of the ground under pier e, uplift of the soil around pile foundation a, tilting of the steel beam of the pedestal c, and collapse of the pedestal by pushing the steel beam to one side, eccentric stress, cracking and damage of pile foundation a, thereby causing safety accidents and distortion of test data.

[0006] Based on this, the utility model designs a pier foundation structure for a large-tonnage pile foundation static load test to solve the above problems. Utility Model Content

[0007] The purpose of the utility model is to provide a pier foundation structure for large-tonnage pile foundation static load test to solve the above technical problems.

[0008] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a pier foundation structure for static load test of large-tonnage pile foundation, comprising a plurality of reinforced concrete bored piles and a corresponding number of steel columns, the lower ends of the steel columns are pre-embedded in the reinforced concrete bored piles, the lower ends of the reinforced concrete bored piles pass downward through the soft soil layer and extend to be embedded in the pebble layer; the plurality of reinforced concrete bored piles are arranged in a transverse and longitudinally spaced array, the transversely adjacent steel columns are connected by a long steel beam, and the longitudinally adjacent steel columns are connected by a short steel beam, the tops of the reinforced concrete bored piles, the top surfaces of the long steel beams and the top surfaces of the short steel beams are all flush with each other, and a carrier plate is laid flat on the top.

[0009] Preferably, both ends of the bottom surface of the long steel beam and both ends of the bottom surface of the short steel beam abut against the top surface of the reinforced concrete cast-in-place pile.

[0010] Preferably, the steel column is a seamless square steel profile, and a pre-embedded steel plate is fixedly welded to the bottom end thereof, and the pre-embedded steel plate is pre-embedded in the reinforced concrete bored pile.

[0011] Preferably, the outer walls of the connecting sides of the steel columns are provided with double-ear plates, the long steel beams and the short steel beams are I-beams of unequal lengths, and both ends of their webs are embedded in corresponding double-ear plates and locked by high-strength bolts.

[0012] Compared with the prior art, the beneficial effects of the utility model are:

[0013] The utility model transfers the static load from the carrier plate to the steel beam and the steel column, and then to the cast-in-place piles, and then passes the cast-in-place piles downward through the soft soil layer and then to the pebble layer, so that the pebble layer effectively bears the load, thereby increasing the bearing capacity of the soft soil foundation, thereby solving the problem of difficulty in detecting large-tonnage static loads in soft soil areas.

[0014] Most of the structure of the utility model is steel structure, and after the pile foundation is inspected, it can be disassembled and reinstalled for reuse, which greatly reduces the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the utility model embodiments, the drawings required for describing the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0017] Figure 2 This is a schematic diagram of the utility model in a separated state;

[0018] Figure 3 yes Figure 2 A schematic diagram of the enlarged structure at point A;

[0019] Figure 4 It is a schematic diagram of the existing ballast platform loading method equipment. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the utility model embodiments to clearly and completely describe the technical solutions in the utility model embodiments. Obviously, the described embodiments are only part of the utility model embodiments, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0021] Example 1 Figure 1-3 As shown, a pier foundation structure for a large-tonnage pile foundation static load test comprises a plurality of reinforced concrete bored piles 1 and a corresponding number of steel columns 2, wherein the lower ends of the reinforced concrete bored piles 1 pass downward through the soft soil layer and extend to be embedded in the pebble layer;

[0022] The lower end of the steel column 2 is embedded in the reinforced concrete pile 1. The steel column 2 is a seamless square steel profile, and a pre-embedded steel plate 6 is fixedly welded at the bottom end. The pre-embedded steel plate 6 is embedded in the reinforced concrete pile 1 as a bearing surface structure at the bottom end of the steel column 2.

[0023] The plurality of reinforced concrete piles 1 are arranged in a horizontal and vertical spaced array. In this embodiment, three groups are arranged horizontally and three groups are arranged vertically. The number of the piles can be increased or decreased according to the actual load applied.

[0024] The steel columns 2 adjacent to each other in the transverse direction are connected by long steel beams 3, and the steel columns 2 adjacent to each other in the longitudinal direction are connected by short steel beams 4, wherein the long steel beams 3 and the short steel beams 4 are I-shaped steels of different lengths;

[0025] The top of the reinforced concrete pile 1, the top surface of the long steel beam 3 and the top surface of the short steel beam 4 are all flush with each other, and a carrier plate 5 is laid flat on the top. The carrier plate 5 and the top surface of the long steel beam 3 and the short steel beam 4 are detachably mounted with bolts;

[0026] The two ends of the bottom surface of the long steel beam 3 and the two ends of the bottom surface of the short steel beam 4 are both in contact with the top surface of the reinforced concrete bored pile 1; and the outer wall of the connecting side of the steel column 2 is provided with a double-ear plate 7, and a plurality of bolt holes are opened on the double-ear plate 7, and bolt holes are opened at both ends of the web 34 of the long steel beam 3 and the short steel beam 4, and the two ends of the web are embedded in the corresponding double-ear plates 7 and locked by high-strength bolts 8. On the one hand, the shear force of the long steel beam 3 and the short steel beam 4 is jointly borne by the high-strength bolts 8 and the reinforced concrete bored pile 1, avoiding stress concentration leading to excessive strain or even overload deformation of local components. On the other hand, the long steel beam 3 and the short steel beam 4 are detachably connected to the steel column 2, so that the equipment can be disassembled after the static load test on the current pile foundation and transferred to the next pile foundation test project for continued use, thereby saving construction costs.

[0027] Implementation method:

[0028] The usual way to deal with the situation where the foundation bearing capacity is insufficient in static load detection in soft soil areas is to carry out large-scale foundation replacement combined with the construction of cement mixing piles. Due to the thick soft soil layers such as silt in this area, the traditional replacement method is costly and the bearing capacity of the treated foundation is difficult to meet the static load bearing capacity requirements.

[0029] according to Figure 4 The weighted platform stacking method equipment shown in the figure is an improved structure of the pier e part. When in use, the device is connected with Figure 4 The pier e structure can be used as a replacement.

[0030] The utility model can effectively transfer the load of static load to the bearing soil layer, and most of the structure is a steel structure. After the pile foundation is tested, it can be disassembled and reinstalled for reuse, which greatly reduces the cost.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the utility model can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the utility model, which should be included in the scope of the technical solution for protection of the utility model.

Claims

1. A pier foundation structure for a large-tonnage pile foundation static load test, characterized in that: The invention comprises a plurality of reinforced concrete bored piles (1) and a corresponding number of steel columns (2), wherein the lower ends of the steel columns (2) are pre-buried in the reinforced concrete bored piles (1), and the lower ends of the reinforced concrete bored piles (1) extend downward through the soft soil layer and are embedded in the pebble layer; the plurality of reinforced concrete bored piles (1) are arranged in a transverse and longitudinal array with intervals, the transversely adjacent steel columns (2) are connected by a long steel beam (3), and the longitudinally adjacent steel columns (2) are connected by a short steel beam (4); the top ends of the reinforced concrete bored piles (1), the top surfaces of the long steel beams (3) and the top surfaces of the short steel beams (4) are all flush with each other in height, and a carrier plate (5) is laid flat on the top.

2. A pier foundation structure for large-tonnage pile foundation static load test according to claim 1, characterized in that: Both ends of the bottom surface of the long steel beam (3) and both ends of the bottom surface of the short steel beam (4) are in contact with the top surface of the reinforced concrete cast-in-place pile (1).

3. The pier foundation structure for large-tonnage pile foundation static load test according to claim 1, characterized in that: The steel column (2) is a seamless square steel profile, and a pre-buried steel plate (6) is fixedly welded to the bottom end thereof; the pre-buried steel plate (6) is pre-buried in the reinforced concrete cast-in-place pile (1).

4. The pier foundation structure for large-tonnage pile foundation static load test according to claim 1, characterized in that: The outer wall of the connecting side of the steel column (2) is provided with a double ear plate (7), and a plurality of bolt holes are provided on the double ear plate (7). The long steel beam (3) and the short steel beam (4) are I-shaped steels of different lengths, and bolt holes are provided at both ends of the web plates (34) of both. The two ends of the web plates are embedded in the corresponding double ear plates (7) and are locked by high-strength bolts (8).

5. The pier foundation structure for large-tonnage pile foundation static load test according to claim 1, characterized in that: The outer walls of the connecting sides of the steel columns (2) are provided with double-ear plates (7); the long steel beams (3) and the short steel beams (4) are I-shaped steels of different lengths, and the two ends of their webs are embedded in the corresponding double-ear plates (7) and are locked by high-strength bolts (8).

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