CN205990622U

CN205990622U - A kind of raft foundation

Info

Publication number: CN205990622U
Application number: CN201620395892.4U
Authority: CN
Inventors: 叶香雄
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-04-20
Filing date: 2016-04-20
Publication date: 2017-03-01
Anticipated expiration: 2026-04-20

Abstract

The utility model discloses a kind of raft foundation, it is characterized in that, when the ratio of raft plate hight degree and raft span of slab is more than or equal to 0.1, middle part 1/3 region arranges that long stake is controlled settling, and edge 1/3 region is arranged stub to adapt to requirement for bearing capacity.The hardened structure of raft 1/3 position hollow out along in the middle of in-plane, engraved structure is arranged on middle 1/3 position along short transverse；In arrangement prestress muscle in the range of raft edges of boards edge 1/4, non-prestressing tendon is arranged in middle part；Pouring expansive concrete in the range of raft edges of boards edge 1/4, middle part pours normal concrete.

Description

A kind of raft foundation

Technical field

This utility model is related to building field, particularly to a kind of raft foundation.

Background technology

China's Development of High-rise Buildings is rapid in recent years, and construction scope and building height are continuously increased, and basic scale is also continuous Expand, as a kind of large-scale base form, raft foundation has the advantages that other base forms many do not possess, how high-rise It is widely used in building.But the hardened structure of raft is bigger due to the concrete scale of construction, and concrete can be released in hydration process Release amount of heat, temperature stress easily makes raft plate cracking, and in addition the hardened structure of raft often goes out in load bearing process The phenomenon of existing corner crack.

Utility model content

The purpose of this utility model is to provide a kind of raft foundation cracking to solve the problems, such as raft plate.

Test shows：When the ratio of raft plate hight degree and raft span of slab is less than 0.1, the hardened structure of raft presents on stress performance Go out the feature of narrowing toward each end broad in the middle, and settle the same i.e. narrowing toward each end broad in the middle of distribution situation, when raft plate hight degree and raft plate across When the ratio of degree is more than or equal to 0.1, the hardened structure of raft presents the big feature in middle little both sides on stress performance, and settles Present contrary trend, i.e. narrowing toward each end broad in the middle, this utility model is arranged to structure according to this stress and Deposition Characteristic.

When the ratio of raft plate hight degree and raft span of slab is less than 0.1, in the middle part of raft plate, 1/3 region arranges that long stake is controlled sinking Fall, the harder soil layer of geology is stretched in long stake, and stub is arranged in edge 1/3 region, and stub length is long pile length 0.6～0.85, short Pile spacing is the 0.85～1.1 of long pile spacing, and concrete length and spacing determine according to place geology.The hardened structure of raft and tradition side Method is identical.

When the ratio of raft plate hight degree and raft span of slab is more than or equal to 0.1, middle part 1/3 region arranges that long stake is controlled Sedimentation, edge 1/3 region is arranged stub to adapt to requirement for bearing capacity, and stub length is long pile length 0.6～0.85, stub spacing For the 0.6～0.8 of long pile spacing, concrete length and spacing determine according to place geology.The hardened structure pair of raft in this utility model Traditional method improves, the hardened structure of raft along 1/3 position hollow out in the middle of in-plane, engraved structure along short transverse be also in Between 1/3 position.In order to alleviate the temperature stress of raft plate further and reduce cost, in conjunction with the force-bearing characteristics of raft foundation, hollow out Structure is 2～2.5m along in-plane isolated edge distance, and engraved structure length and width is 0.8～1.2m, and engraved structure is thick Degree is at middle 1/3 position along short transverse.

According to raft foundation bottom stress distribution feature, raft plate corner occurs that stress concentration easily ftractures, from raft plate Arrangement prestress muscle in the range of edge 1/4, non-prestressing tendon is arranged in middle part.Sequence of PR tension is using as follows：First The deformed bar in the short direction of tensioning, equidirectional deformed bar tensioning using jumping every tensioning, that is, after first reinforcing bar of tensioning again The 3rd reinforcing bar of tensioning and the like, the whole tensioning of deformed bar in short direction finish after tensioning length direction again prestressing force Reinforcing bar, deformed bar control stress for prestressing is 0.72 characteristic value of strength of steel bar.

In order to prevent raft plate corner crack further, in the range of raft edges of boards edge 1/4, pouring expansive concrete, pars intermedia Position pours normal concrete.Concrete vibrating is pulled out slowly using inserting soon, prevents that vibrating time is too short to lead to concrete uneven Or overlong time leads to the phenomenons such as serious laitance；Take secondary vibration method, improve concrete density, timely exclusion table after pouring Area water, divides after secondary receipts light and smears pressure, produces to sink and moulds crack after preventing plastic concrete sedimentation.

Three layers of casting concrete are divided along short transverse, every layer pours thickness for the 1/3 of raft plate gross thickness, the second layer during construction Concrete lays precast slab at hollow out position, and precast concrete is shelved on above casting concrete, and shelving length is 200～300mm.

Cover double-plastic after the completion of concreting immediately and straw bag carries out heat and moisture preserving maintenance, in maintenance processes Strengthen concrete measuring temperature monitoring work, to adjust the covering number of plies of straw bag in time.

This utility model has the advantages that mechanical property is good, safe and reliable, has preferable application prospect.

Brief description

Fig. 1 is raft foundation floor map, and Fig. 2 is raft foundation generalized section.

Accompanying drawing mark：1st, raft plate, 2, precast slab, 3, long stake, 4, stub.

Specific embodiment

Below in conjunction with accompanying drawing, the present embodiment is described in detail.

In the middle part of the present embodiment, 1/3 region arranges that long stake 3 is controlled settling, and edge 1/3 region is arranged stub 4 to adapt to hold Load power requires, and stub 4 length is long stake 3 length 0.7, and stub 4 spacing is the 0.7 of long stake 3 spacing, concrete length and spacing according to Place geology is determining.The hardened structure of raft 1/3 position hollow out along in the middle of in-plane, engraved structure is arranged on centre along short transverse 1/3 position.Engraved structure is 2.5m along in-plane isolated edge distance, and engraved structure length and width is 1m, engraved structure Thickness is at middle 1/3 position along short transverse.

According to raft foundation bottom stress distribution feature, raft plate 1 corner occurs that stress concentration easily ftractures, from raft plate Arrangement prestress muscle in the range of 1 edge 1/4, non-prestressing tendon is arranged in middle part.Sequence of PR tension is using as follows：First The deformed bar in the short direction of tensioning, equidirectional deformed bar tensioning using jumping every tensioning, that is, after first reinforcing bar of tensioning again The 3rd reinforcing bar of tensioning and the like, the whole tensioning of deformed bar in short direction finish after tensioning length direction again prestressing force Reinforcing bar, deformed bar control stress for prestressing is 0.72 characteristic value of strength of steel bar.

Pouring expansive concrete in the range of raft plate 1 edge 1/4, middle part pours normal concrete.Concrete shakes Smash and pulled out slowly using slotting soon；Take secondary vibration method, improve concrete density, after pouring, exclude surface area water, secondary receipts in time Divide after light and smear pressure, produce to sink after preventing plastic concrete sedimentation and moulds crack.

Three layers of casting concrete are divided along short transverse, every layer pours thickness for the 1/3 of raft plate 1 gross thickness, second during construction Layer concrete lays precast slab 2 at hollow out position, and precast concrete is shelved on above casting concrete, shelving length For 250mm.

Claims

1. a kind of raft foundation, is characterized in that middle part 1/3 region arranges that long stake is controlled settling, edge 1/3 region arrangement is short Adapting to requirement for bearing capacity, stub length is long pile length 0.6～0.85, and stub spacing is the 0.6～0.8 of long pile spacing for stake, Concrete length and spacing determine according to place geology；The hardened structure of raft 1/3 position hollow out, engraved structure edge along in the middle of in-plane Short transverse is arranged on middle 1/3 position；Engraved structure is 2～2.5m along in-plane isolated edge distance, and engraved structure is long Degree and width are 0.8～1.2m.

2. raft foundation according to claim 1, is characterized in that in arrangement prestress muscle in the range of raft edges of boards edge 1/4, Non-prestressing tendon is arranged in middle part.

3. raft foundation according to claim 1, is characterized in that pouring expansion coagulation in the range of raft edges of boards edge 1/4 Soil, middle part pours normal concrete.