The mortar must be filled tightly, and the outer wall surface must be pointed with raw mortar.
As pointed out by the court of first instance, as the construction unit, the urban investment company will the preliminary construction drawings (commonly known as white drawings) that have not been reviewed and signed and sealed by the design institute and designers It violates the basic construction procedures of the construction project by submitting it to the water supply corporation and requiring it to carry out the construction according to this method; it does not actively deal with or reply to the problems found by the water supply corporation and the supervision company after reporting to them during the construction process, and the supervision company in [2008] The completely legitimate and necessary suggestion for parallel testing of materials, mortar and concrete test blocks used in the project mentioned in No.
“Therefore, the court finds that the violation and omission of the urban investment company are the important reasons for the collapse accident.
It should be considered that if the original design structure drawing of the design institute does not exist For design defects, when repairing and reconstructing the collapsed section, it is only necessary to restore according to the original design drawing, and there is no need to make major changes to the original design drawing.
The design institute reviewed the left and right parts of the collapsed section, and the construction quality of the reviewed part should be basically consistent with that of the collapsed section.
Design requirements: the retaining wall structure adopts mortar block stone with mortar grade of M7.5, the compressive strength of the stone is not less than 30MPa, the block stone is roughly square, and the minimum thickness is not less than 25cm.
Some omissions of the urban investment company and the supervision company cannot be exempted or mitigated by the Water Corporation The legitimate reason for the legal liability that should be borne according to law and contract.
Although the construction supervision contract of this case stipulates that the supervision company” shall report to the client when it finds that the design documents do not comply with relevant provisions or contract provisions “, considering the construction supervision contract of this case It is clearly stipulated that the name of the supervision project is “construction supervision of urban flood control project in Baojing County with ADB loan”, the supervision stage is “supervision during construction”, and the urban investment company fails to prove that it is preparing the construction design drawings (including initial design and changed design) Before delivery to the water supply company, the construction design drawings have been sent to the supervision company for review and issuance as required.
This obviously increases the section size of the retaining wall.
Due to the poor masonry quality of the wall body, the wall body does not have the ability to resist lateral pressure in case of slight external force, resulting in shear failure of the wall body and then overturning and collapse.
The actual construction situation is that the block stone size of the retaining wall in this section is too small, a large number of walls are not built with mortar, and the assembly method is chaotic.
This is enough to prove that there are certain design defects in the original design structural drawing of the design institute.
“The Water Resources Corporation did not explicitly deny the review report.
The design institute appealed that it did not have the objective conditions and organizational ability to change the design at will, so it should be considered that the reason was basically tenable In the judgment reason part, the trial court found that the design institute violated the construction procedures and arbitrarily changed the design during the project construction, and the evidence was insufficient, which was not recognized by the court.
Investigation opinions of the expert group It is also recorded that the design institute has used the preliminary survey report as the basis for construction design.
The state had corresponding regulations on the relevant procedures of design change.
The design institute also clearly pointed out in the review report:” many drainage pipes on the wall are not connected, This increases the water pressure behind the wall, which is extremely unfavorable to the stability of the wall body; At the same time, the block stone body of the wall body is too small, the mortar is not full, the masonry is not dense, there are many cavities, the wall structure is relatively loose and cannot be cemented as a whole, which is unfavorable to the shear and tensile strength of the wall body.
The Water Corporation shall bear 70% of the legal liability for the collapse accident.
However, the supervision company failed to strictly require all the quality problems existing in the construction of the water head office to be seriously rectified, and certified and issued some projects with quality problems during measurement, so as to prevent collapse as much as possible Therefore, the Institute determined that the failure of the supervision company to strictly adhere to the quality standards was the indirect and secondary reason for the failure to prevent the collapse accident.
However, according to the investigation opinions of the expert group, part of the basement of the collapsed retaining wall was placed on the surface of the foundation rock and was not embedded with the bedrock, resulting in sliding.
Especially, the foundation part is filled and stacked.
It is certain that the urban investment company has not sent the white drawings to the supervision company for filing and review before submitting the white drawings to the water supply company for construction according to this drawing, so it is not appropriate to recognize that the supervision company has the obligation to review and issue the construction design drawings As a construction supervisor, the scope of responsibility advocated by the management company does not include the appeal reasons for supervising the design quality problems, which is basically tenable.
The Water Corporation refuses to comprehensively, timely and effectively rectify the construction quality problems pointed out by the supervision company, and even once resisted the supervision company to perform the supervision duties according to laws and regulations, which shall be considered as serious.
3 work contact sheet is only “witness sampling and joint submission for inspection”.
The water head office agreed to submit it in accordance with the regulations of the urban investment company White map construction itself is also in violation of regulations and shall bear corresponding legal responsibilities.
“We can’t think that the statement of China National Water Corporation is entirely to evade responsibility, and some of its statements are in line with the reality.
The original design defect of the design institute is the direct and important reason for the collapse accident..
Click the “construction skills” above to pay attention to me, right? A fair trial for the supervisor is rare! Specialty, method and procedure are very important for supervision! Refueling supervisor! give the thumbs-up! Collect and learn! The expert group’s expert opinion clearly states: “After site investigation on the site conditions of collapsed and non collapsed retaining walls, the expert group believes that the retaining wall has the following problems: the masonry method of retaining wall body seriously violates the requirements of design drawings and construction specifications, and the masonry quality of retaining wall body is poor.
The design institute uses the preliminary survey report as the basis for construction design, and there is no design for embedding the retaining wall and bedrock, which obviously does not comply with the relevant national regulations, leaving potential accidents of sliding and collapse.
The mortar at the collapse site is basically no block, all of which are loose coarse sand, and the masonry mortar strength is too low and very not full.
In the objection letter, the Water Corporation said that “the bedrock of this section is red sandstone, which is easy to be weathered and softened under the action of water and air, which is easy to cause uneven settlement of the foundation and may lead to cracking of the masonry retaining wall, Under the action of filling pressure, the foundation surface of the retaining wall dumped along the cracking surface ·································································································.
“Although the Water Corporation disagreed with the expert group’s appraisal opinion and raised an objection, in the objection letter, it did not directly deny the views clearly put forward in the expert group’s appraisal opinion, but argued that the collapse was caused by other reasons.
Therefore, the Institute believes that the original design defects of the design institute are a direct and important cause of collapse accidents Reasons.
However, when repairing and reconstructing the collapsed retaining wall, the design institute changed the design scheme from the original balance weight retaining wall, with the bottom width of 7.6-8.4m, the balance platform width of 8.03-9.9m and the top width of 0.5m to the surface ruler of the original design section The foundation is widened and thickened, the platform elevation is increased from 205m to 208.53m, the embankment top width is changed to 1m, and the mortar strength is changed from M7.5 to M10.
The review report indirectly proves the expert group’s evaluation opinions to a considerable extent Therefore, the Institute determined that the poor masonry quality of the retaining wall body constructed by the Water Corporation was the direct and fundamental cause of the collapse accident.
The poor masonry quality of the retaining wall body under the construction of the water head office was the direct and fundamental reason for the collapse accident.
